Euclid is a city in Cuyahoga County, Ohio, United States. Located on the southern shore of Lake Erie, it is an inner ring suburb of Cleveland. The population was 49,692 at the 2020 census, making it the fourth largest city in Cuyahoga County.

The City of Euclid was originally a part of Euclid Township, first mapped in 1796 and named for Euclid of Alexandria, the ancient Greek mathematician. The first sparse settlement in the township began in 1798, with major settlement beginning in the spring of 1804. The first settlers in what is now the City of Euclid were Joseph and Chloe Burke, David and Mary Dille and William and Jamima Coleman, and their children. Following the Civil War the lake plain of Euclid Township was known for numerous excellent vineyards. Euclid Village incorporated out of the northeast portion of the township in 1903. It developed as an industrial center in the early 20th century, and became a city in 1930.

Euclid is the city where Charles F. Brush created the Arc Lamp in 1876. The cordless telephone was invented in Euclid by George Sweigert in 1969.

Euclid is the site of the 1926 U.S. Supreme Court case Euclid v. Ambler. The case opened the doors for municipalities across the United States to establish zoning ordinances.

In June 2011, Lincoln Electric installed a 2.5 Megawatt wind turbine. At 443 feet, it is the largest in Ohio and one of the largest in North America

Euclid is located at 41°35′44″N 81°31′9″W / 41.59556°N 81.51917°W / 41.59556; -81.51917 (41.595563, -81.519176).

According to the United States Census Bureau, the city has a total area of 11.48 square miles (29.73 km2), of which 10.63 square miles (27.53 km2) is land and 0.85 square miles (2.20 km2) is water. It is on the shore of Lake Erie, with a beachfront area along its north edge.

Bordering Euclid are Cleveland on the west, South Euclid and Richmond Heights on the south, Willowick, Wickliffe, and Willoughby Hills on the east, and Lake Erie on the north.

It is part of the Lake Erie Snowbelt region, prone to snow squalls blowing off Lake Erie, particularly before the lake freezes over in winter.

As of the census of 2010, there were 48,920 people, 22,685 households, and 12,187 families living in the city. The population density was 4,602.1 inhabitants per square mile (1,776.9/km2). There were 26,037 housing units at an average density of 2,449.4 per square mile (945.7/km2). The racial makeup of the city was 43.8% White, 52.6% African American, 0.2% Native American, 0.7% Asian, 0.3% from other races, and 2.3% from two or more races. Hispanic or Latino of any race were 1.6% of the population.

There were 22,685 households, of which 27.8% had children under the age of 18 living with them, 28.4% were married couples living together, 20.9% had a female householder with no husband present, 4.4% had a male householder with no wife present, and 46.3% were non-families. 41.4% of all households were made up of individuals, and 14.5% had someone living alone who was 65 years of age or older. The average household size was 2.13 and the average family size was 2.91.

The median age in the city was 61 years. 22.9% of residents were under the age of 18; 7.8% were between the ages of 18 and 24; 24.3% were from 25 to 44; 28.9% were from 45 to 64; and 15.9% were 65 years of age or older. The gender makeup of the city was 44.8% male and 55.2% female.

As of the census of 2000, there were 52,717 people, 24,353 households, the 13,491 families living in the city. The population density was 4,923.2 inhabitants per square mile (1,900.9/km2). There were 26,123 housing units at an average density of 2,439.6 per square mile (941.9/km2). The racial makeup of the city was 66.36% White, 30.57% African American, 0.12% Native American, 0.94% Asian, 0.02% Pacific Islander, 0.35% from other races, and 1.64% from two or more races. Hispanic or Latino of any race were 1.15% of the population.

There were 24,353 households, out of which 24.9% had children under the age of 18 living with them, 36.3% were married couples living together, 15.2% had a female householder with no husband present, and 44.6% were non-families. 39.7% of all households were made up of individuals, and 16.1% had someone living alone who was 65 years of age or older. The average household size was 2.14 and the average family size was 2.89.

In the city, the population was spread out, with 22.3% under the age of 18, 6.8% from 18 to 24, 30.7% from 25 to 44, 21.0% from 45 to 64, and 19.2% who were 65 years of age or older. The median age was 39 years. For every 100 females, there were 84.0 males. For every 100 females age 18 and over, there were 79.1 males.

The median income for a household in the city was $35,151, and the median income for a family was $45,278. Males had a median income of $35,914 versus $28,528 for females. The per capita income for the city was $19,664. About 7.1% of families and 9.7% of the population were below the poverty line, including 11.9% of those under age 18 and 11.2% of those age 65 or over.

91.8% spoke English, 1.8% Spanish, 1.3% Croatian, 1.2% Slovene, and 0.62% Italian as their first language.

Euclid is home to a variety of ethnic groups. One of the largest is the city's historic Slovene population. There are a number of streets in Euclid that commemorate the Slovenian influence on Euclid, including Recher, Mavec, Drenik, Grdina, Trebec, Mozina, Kapel, and Ljubljana. Today, Euclid's largest ethnic population is African American, while also containing sizeable populations of Croats, Irish and Italian communities.

Euclid is the home to both the main plant and corporate headquarters of the Lincoln Electric Company.

The Euclid Company of Ohio was a company that specialized in heavy equipment for earthmoving, namely dump trucks, loaders and wheel tractor-scrapers. It operated in the US from the 1920s to the 1950s, when it was purchased by General Motors. It was later purchased by Hitachi Construction Machinery.

Euclid is home to the National Cleveland-Style Polka Hall of Fame tracing Cleveland-Style Polka from its Slovenian roots

Euclid is home to the Euclid Pony Baseball League, founded in 1951; the annual CABA High School World Series baseball tournament, and the Greater Cleveland Slo-Pitch Softball Hall of Fame

Euclid is partly home to Euclid Creek Reservation, a property of Cleveland Metroparks which shares space in South Euclid, Cleveland and Richmond Heights Euclid Beach Park was originally part of Euclid Township, until the boundaries were redrawn in the early 1900s.

Walk Two Moons by Sharon Creech was partly set in Euclid. The 1987 movie Light of Day was partially filmed in Euclid.

The city uses a Mayor-Council government and there are eight councilors.

Euclid City Schools is the local school district. Euclid High School is the local public high school.

Our Lady of the Lake, a Roman Catholic elementary school and church, is located on Lakeshore Boulevard. Saints Robert and William Catholic School, also a Roman Catholic elementary school and church, is located on East 260th Street.

Euclid houses the Euclid Public Library, ranked third in the nation in the 50,000 population category in 2007, and has been recognized in the Top Ten of the HAPLER Public library Ratings[citation needed]