A few subsequent changes to Erie County's boundaries occurred shortly after its initial formation.

Near the Huron River are several ancient earthwork mounds and enclosures constructed by early indigenous peoples.

The surface is generally level, and the soil alluvial and exceedingly fertile.

35.7% were of German, 9.2% Irish, 8.2% English, 8.1% Italian, and 7.8% American ancestry according to Census 2000.

In 2008, the Census Bureau announced that the county's population had declined to an estimated 77,323 by July 1, 2007.

[14] As of the 2010 United States Census, there were 77,079 people, 31,860 households, and 21,011 families residing in the county.

[15] In terms of ancestry, 38.8% were German, 15.2% were Irish, 11.7% were English, 8.5% were Italian, and 4.6% were American.

[20][21] Erie County's courthouse at 323 Columbus Avenue in Sandusky was built in 1872 by Cleveland architects Myer and Holmes in a richly ornamented Second Empire style.

Most of the façade was remodeled beginning in 1936 in Art Deco in a WPA project led locally by architect Henry Millott.

Some of the original façade remains visible around the bottom row of windows.

[22] All or part of eleven school districts serve Erie County and its residents: