Peter was the son of Basil Lamar and Mary Jane Patton. He married Sarah Cobb Benning about 1809 in Lincoln County, Georgia. He is buried at the Lamar Family Cemetery in Lincolnton, Lincoln County, Georgia.

Peter represented Lincoln County, GA in the House of Representatives in 1811-12
Clerk of the Superior Court of Lincoln County from 1816-1834
Represented the county in the State Senate from 1834 to 1838
In War of 1812, 4th Regt, Booth's GA Volunteer Militia, Capt.
Founder of Lincolnton, Georgia
Gave land for first Presbyterian Church, The County Courthouse, and Jail
Styled "The King of Lincoln"
Peter built his house in Lincolnton in 1823. It is now called the Lamar-Blanchard House and is the only surviving representation of its type of plantation type home in the downtown area. It is used as the Welcome Center for Lincoln County and the office of the Chamber of Commerce. 03 Mar 1823. Deed was made by Peter for land west of the original courthouse in Lincolnton. The Old Union Church was built in that year on the land. It was the first and only church in the town until after the Civil War. The church was used as a school also.
Great-grandfather of Dr. Lucian Lamar Knight