Post 175 was organized by sixteen Veterans on September 27, 1945. The Post was granted its Permanent Charter in April 1946.  The 16 founding members were: R.B. Bullock; C.H. Hall; B.A. Humphries; C.R. Jenkins; W.F. Knox; C.D. Mayer; J.G. Payne; H.G. Puller; Joseph Rotella; B.I. Rowe; L. Hampton Stewart; B.T. Talley; Lloyd L. Traylor; Harold Warren; W.F. West; and E. Ray Winters.

American Legion Post 175 was initially formed by a group of sixteen Veterans in 1945, and has grown its membership to nearly 400 "war time" Veterans to date. It has served the local and 'extended' community for over 70 years.

Post 175, initially organized on September 27, 1945, had a nice little house across the street from the Mechanicsville Recreation Building as its first Post home. The Post home later moved to a small house on Route 301, next to the Timberlake Realty Company.  Post 175 moved to the back room of Johnson's Grocery Store on Atlee Road in 1978, where it remained until the dedication of its current home at 8700 Bell Creek Road in Mechanicsville, Virginia on October 21, 2011.

The current Post home is also home for the following affiliated organizations: American Legion Auxiliary; Sons of the American Legion; and American Legion Riders.

Some of Post 175's sponsorships include: three Junior Reserve Officer Training Corps (JROTC) units; Scouts BSA Cub Pack and Troop 553; and a champion American Legion Baseball team.