Following independence, the sovereign State of Maryland formed Washington County on September 6, 1776, by the division of Frederick County. At the same time, a portion of Frederick County became part of the newly created Montgomery County along with portions from Prince George's County and Charles' County, and was named for General Richard Montgomery. Washington County as created included land later to become Allegany County (created in 1789) and Garrett County (included in Allegany County when it was created in 1789, but separated from Allegany County in 1872). Washington County thus originally included the entire western part of the state.