The county was founded in 1849 and is named for Alexander Ramsey, the first governor of the Minnesota Territory.

[4] Ramsey County is part of the Minneapolis–Saint Paul-Bloomington, MN-WI Metropolitan Statistical Area.

Ramsey County remained largely farmland until small villages began to appear in the late 19th century, with the incorporation of North St. Paul in 1887, New Brighton in 1891, and White Bear Lake in 1921.

In 2020, Democratic nominee Joe Biden received the largest share of the vote for any candidate in the county's history, with over 71%.

In addition to enforcing the law, the office provides town police services under contract to Arden Hills, Falcon Heights, Little Canada, North Oaks, Shoreview, Vadnais Heights, and White Bear Township.

[8] The Ramsey County Sheriff's office provides a number of unique services as mandated by law.

It is responsible for the county jail, more officially the Adult Detention Center, which can hold 500 prisoners and has a staff of about 150.

[13] Amtrak offers daily intercity passenger rail service on the Empire Builder from Union Depot in Saint Paul.

[14] Light rail service is provided by Metro, a light rail and bus rapid transit system operated by Metro Transit that connects several communities in Ramsey and Hennepin Counties.

[15] The Metro Green Line connects Union Depot to Target Field station in Minneapolis, in neighboring Hennepin County.

US 52 runs from South Saint Paul in Dakota County north to downtown Saint Paul where it meets I-94 and turns west to run concurrently with it all the way to the North Dakota border.

From the south, US 61 runs concurrently with US 10 and then I-94 until it continues northeast on surface streets through the East Side of Saint Paul.

From Saint Paul, US 61 continues north through Maplewood and White Bear Lake before crossing the border into Washington County.

According to the 2010–2015 American Community Survey, the largest ancestry groups were German (26.0%), Irish (11.5%), Norwegian (9.9%), and Swedish (7.4%).