Waltham (/ˈwɔːlθæm/ WAWL-tham) is a city in Middlesex County, Massachusetts, United States, and was an early center for the labor movement as well as a major contributor to the American Industrial Revolution. The original home of the Boston Manufacturing Company, the city was a prototype for 19th century industrial city planning, spawning what became known as the Waltham-Lowell system of labor and production. The city is now a center for research and higher education, home to Brandeis University and Bentley University as well as industrial powerhouse Raytheon Technologies. The population was 65,218 at the census in 2020.

Waltham has been called "watch city" because of its association with the watch industry. Waltham Watch Company opened its factory in Waltham in 1854 and was the first company to make watches on an assembly line. It won the gold medal in 1876 at the Philadelphia Centennial Exposition. The company produced over 35 million watches, clocks and instruments before it closed in 1957.

Waltham was first settled in 1634 as part of Watertown and was officially incorporated as a separate town in 1738. Waltham is most likely named for Waltham Abbey in the County of Essex, England. The first record of the name is from the articles of incorporation, dated January 15, 1738. The name derives from the Anglo-Saxon words, weald or wald "forest" and ham "homestead" or "enclosure." Waltham had no recognizable town center until the 1830s, when the nearby Boston Manufacturing Company gave the town the land that now serves as its central square.

In the early 19th century, Francis Cabot Lowell and his friends and colleagues established in Waltham the Boston Manufacturing Company—the first integrated textile mill in the United States, with the goal of eliminating the problems of co-ordination, quality control, and shipping inherent in the subcontracting based textile industry. The Waltham–Lowell system of production derives its name from the city and the founder of the mill.

The city is home to a number of large estates, including Gore Place, a mansion built in 1806 for former Massachusetts governor Christopher Gore, the Robert Treat Paine Estate, a residence designed by architect Henry Hobson Richardson and landscape architect Frederick Law Olmsted for philanthropist Robert Treat Paine, Jr. (1810–1905), and the Lyman Estate, a 400-acre (1.6 km2) estate built in 1793 by Boston merchant Theodore Lyman.

In 1857, the Waltham Model 1857 watch was produced by the American Watch Company in the city of Waltham, Massachusetts. In the late 19th and early 20th century, Waltham was home to the brass era automobile manufacturer Metz, where the first production motorcycle in the U.S. was built.

Another first in Waltham industrial history involves the method to mass-produce the magnetron tube, invented by Percy Spencer at Raytheon. During World War II, the magnetron tube technology was applied to radar. Later, magnetron tubes were used as components in microwave ovens.

Waltham was also the home of the Walter E. Fernald State School, the western hemisphere's oldest publicly funded institution serving people with developmental disabilities. The storied and controversial history of the institution has long been covered by local and, at times, national media.

The name of the city is pronounced with the primary stress on the first syllable and a full vowel in the second syllable, /ˈwɔːlθæm/ WAWL-tham, though the name of the Waltham watch was pronounced with a reduced schwa in the second syllable: /ˈwɔːlθəm/. At one time, most people would have pronounced it in the British way, "Walthum", but when people came to work in the mills from Nova Scotia, the pronunciation evolved. The local version became a phonetic sounding to accommodate French speakers who could not pronounce it in the British way. In some areas, the city is referred to as "The Waltham".

Waltham is located at 42°22′50″N 71°14′6″W / 42.38056°N 71.23500°W / 42.38056; -71.23500 (42.380596, −71.235005), about 11 miles (18 km) north-west of downtown Boston, Massachusetts, and approximately 3 miles (4.8 km) northwest of Boston's Brighton neighborhood. The heart of the city is Waltham Common, which is home to Waltham City Hall and various memorial statues. The Common is on Main Street, which is home to several churches, the Waltham Public Library, and Post Office.

The city stretches along the Charles River and contains several dams. The dams were used to power textile mills and other endeavors in the early years of the industrial activity.

According to the United States Census Bureau, the city has a total area of 13.6 square miles (35 km2), of which 12.7 square miles (33 km2) is land and 0.9 square miles (2.3 km2) (6.69%) is water.

Waltham has several neighborhoods or villages, including:

It is bordered to the west by Weston and Lincoln, to the south by Newton, to the east by Belmont and Watertown, and to the north by Lexington.

As of the census in 2020, there were 65,218 people and 23,891 households in the city. The population density was 5,117.9/mile². According to 2021 census estimates, the racial makeup of the city was 70.5% White, 7.6% Black or African American, 0.5% Native American or Alaska Native, 11.8% Asian, 0.0% Pacific Islander, 5.3% from other races, and 4.3% from two or more races. Hispanic or Latino of any race were 14.3% of the population.

There were 23,891 households, 19.8% of which included children under the age of 18 and 28.4% with people 65 and older. 39.7% of households were married couples living together, 9.9% cohabitating couples, 21.2% male householders with no partner present, and 29.2% female householders with no partner present. The average household size was 2.29 and the average family size was 3.02.

32.7% of households spoke a language other than English at home.

The age distribution is as follows: 13.7% under 18, 20% from 18 to 24, 30.6% from 25 to 44, 9.9% from 45 to 64, and 14.6% 65 or older. The median age was 34. The population was 48.3% male and 51.7% female.

The median income for a household was $95,851, and per capita was $44,977. In 2020, 9.2% of the population and 5% of families lived below the poverty line. 11.7% of those under 18 and 8.45% of those 65 and older lived below the poverty line.

As of 2020, 26.6% of Waltham residents were born outside of the United States. Of foreign-born residents, 41.5% were born in Asia, 32.7% in Latin America, 11.9% in Europe, and 9.7% in Africa.

Waltham's combination of population (especially in central and south Waltham) parks, public transit, stores, and trails gives it 62 (out of 100) walkability ranking on walkscore.com.

Moody Street in downtown Waltham offers its own brand of entertainment with a colorful assortment of shops, restaurants, and bars. Moody Street's booming nightlife, convenience to the commuter rail and lower rents have attracted younger professionals to Waltham in growing numbers in recent years. Moody Street is also referred to as "Restaurant Row" and has become a destination because of the number, variety and quality of its locally owned restaurants. The city of Waltham has a free "Tick Tock Trolley" on Thursday, Friday and Saturday evenings from 6pm–11pm for visitors that provides easy access to local municipal parking lots.

Starting in 2020, the City of Waltham in Massachusetts has shut down a large portion of the main road, Moody St., to vehicular traffic from May 1 until October 31 annually. Moody Street is lined with restaurants and other small businesses but typically has high volumes of automobile passage. In an effort to assist these businesses in a difficult time, the Waltham Traffic Commission closed off a segment of the road to allow businesses to have outdoor dining and storefronts amidst the COVID-19 pandemic. Bus stops that would typically be on the blocked off part of Moody St. are temporarily relocated to nearby spots.

Restaurants are supportive of the closure, as they can offer outdoor seating and increase their capacity for business. However, Moody Street has a variety of other businesses like small grocery stores, clothing stores, and jewelers. Some of these non-restaurant business owners oppose repeating the plan in the future, arguing that closing off the road makes their businesses less accessible due to a lack of automobile access. While Waltham has included a variety of stakeholders in the process of the street closure, it is crucial that they continue to do so in order to continue using a democratic process for city-wide decision-making.

For over 25 years, the Waltham Arts Council has sponsored "Concerts On Waltham Common", featuring a different musical act each week of the summer, free of charge to attendees. "Concerts On Waltham Common" was created and organized by Stephen Kilgore until his death in 2004.

The Rose Art Museum at Brandeis University is devoted to modern and contemporary art. The Rose holds a variety of exhibitions and programs, and collections are free and open to the public.

The city's history is also celebrated at a number of museums, monuments, and archives. The Charles River Museum of Industry & Innovation, the Waltham Watch Factory historic district, the Gore Estate, the Lyman Estate, and the Robert Treat Payne Estate are among the most well known of the 109 sites in the city on the National Register of Historical Sites. Many festivals are held at these sites each year, such as the annual sheep shearing festival at the Gore Estate. The National Archives and Records Administration Northeast regional branch is located in Waltham. The Waltham Public Library has extensive archives regarding the city's history. The Waltham Museum is devoted solely to the history of the city. Mark Gately is the only stakeholder left of the Waltham Museum.

Waltham is known for its embracing of literary arts. Local author Jessica Lucci has written a series of books about Waltham which can be found at the Waltham Museum, The Waltham Historical Society, and many other regional establishments devoted to promoting literary arts.

The Waltham Mills Artists Association is located in one of the former factories of the Boston Manufacturing Company. The WMAA Open Studios takes place each year on the first weekend of November. The 76 artists of the WMAA open their homes and studios to the public. Works of all media imaginable are demonstrated, displayed and discussed.

The Waltham Philharmonic Orchestra, a civic symphony of the MetroWest area, began in 1985 under the direction of local musicians David J. Tierney and Harold W. McSwain, Jr. With almost 60 professional, semi-professional, and amateur musicians, the orchestra's mission is to provide the Waltham community with the opportunity to perform in and attend classical concerts of the highest quality. WPO musicians come from Waltham as well as from Boston and surrounding communities. The ensemble includes players of a wide range of ages and professions.

There are five to six concerts throughout the season, including one that features the winner of the annual Youth Concerto Competition, which provides opportunities for young musicians to perform solo works with the WPO. Annual concerts have included summer Concerts on the Common and the December Holiday Pops.

Waltham is home to the Waltham Symphony Orchestra, a high-level semi-professional civic orchestra. The 55 piece orchestra performs five concerts each season at the Kennedy Middle-school Auditorium. Its music director is French-born American conductor, Patrick Botti. Open space in the city is protected by the Waltham Land Trust.

Waltham embraces its ethnic diversity in a number of festivals. The annual Latinos en Acción Festival celebrates the many Puerto Rican, Mexican, Peruvian, and Guatemalan residents. It is held by Latinos in Action, a local nonprofit group that helps the Latino population register to vote, understand the laws and find scholarships. The festival includes a parade, music, food, and a beauty pageant.

Waltham has in recent decades become a center for Ugandan culture, with an estimated 1500 Ugandans living in the city, leading some to call Waltham "Little Kampala". The Ugandan North America Association is headquartered in Waltham, along with St. Peters Church of Uganda Boston, as well as Karibu, a well regarded Ugandan eatery. Wilberforce Kateregga, a Ugandan immigrant to Waltham has since established Waltham College Uganda in Seeta Nazigo, Uganda, a boarding school for over 300 orphans and children affected by AIDS. The school was named in honor of Kateregga's new home city.

Among the companies based in Waltham are the defense contractor Raytheon, medtech corporation PerkinElmer, biopharmaceutical services provider Paraxel, energy supply company Global Partners, data services provider Lionbridge, Steel Connect, broker-dealer Commonwealth Financial Network, technology companies Care.com and StudentUniverse, research and development organization Education Development Center, Inc. (EDC), provisioner of scientific instrumentation Thermo Fisher Scientific, and the marketing firm Constant Contact. Footwear manufacturer Wolverine World Wide, Inc. moved their regional headquarters from Lexington to the CityPoint campus in July 2016. C & J Clark America, Inc. moved their headquarters from Newton to the Polaroid site in October 2016. Retail activity is concentrated on Main Street, Moody Street, Lexington Street, River Street, parts of Route 60, and the First Avenue area. New retail development has also been active at a former Polaroid site.

According to the city's 2018 Comprehensive Annual Financial Report, the top ten non-city employers in the city are as follows.

Waltham is home to:

The Waltham Public Schools system includes seven elementary schools (Northeast, Fitzgerald, MacArthur, Plympton, Whittemore, Stanley, and the Waltham Dual Language Elementary School), two middle schools (McDevitt, Kennedy), and one senior high school (Waltham High School).

Waltham High School's sports teams had been referred to as the Watchmen and the Crimson, before they changed the name to the Hawks.

Waltham is governed by a mayor and a city council. The current mayor is Jeanette A. McCarthy. There are 15 members of the city council, each elected to two-year terms in non-partisan elections. The current president of the city council is John J. McLaughlin.

The city is in Massachusetts's 5th congressional district and is currently represented in the United States House of Representatives by Katherine Clark. Waltham is also represented in the Massachusetts House of Representatives by State Representative John J. Lawn and State Representative Thomas M. Stanley, and in the Massachusetts Senate by Senator Michael Barrett.

Waltham is close to several U.S. interstate highways. Interstate 95, multiplexed with Route 128, runs through the western part of the city. Exits in Waltham are 26, 27, and 28. Interstate 90, which is also the Massachusetts Turnpike, is just to the south in Newton. Due to its proximity to the center of the Greater Boston metropolitan area, a number of state highways are within a few miles.

The MBTA commuter rail has two stops in Waltham as part of the Fitchburg-Boston Line: one in Central Square Waltham across from the City Hall and one near Brandeis University.

MBTA bus service also covers the city, including routes 61, 70, 170, 505, 553, 554, 556 and 558.

The Charles River runs through Waltham, and bike and walking paths cover most of the south bank, as well as part of the north bank from Prospect Street to Moody Street. Some commuters ride the path to offices in Cambridge and Boston.

The city of Waltham is protected by the 166 full-time, paid firefighters of the city of Waltham Fire Department (WFD).[104] Established in 1816, the Waltham Fire Department is currently organized into three divisions of operations: fire suppression, fire prevention, and training.

Armstrong Ambulance Service currently provides 24/7 Advanced Life Support emergency medical services to the City of Waltham.[105]

Waltham is home to the Waltham News Tribune (formerly The Daily News Tribune), a weekly paper which is published each Thursday, year-round owned by Gatehouse Media. The Waltham Patch covers the local, daily news and invites locals to post their own blogs, events and opinion online only.[106] In 2018, Waltham writer Jessica Lucci was chosen as the "Mayor" of Waltham Patch. WCAC-TV is the cable access and provides opportunities for community members to learn how to create their own local-interest television programming. Waltham news sometimes appears in The Boston Globe's GlobeWest section, as well.