U.S. Tri-State Corners, benchmark table

Arranged generally from west to east and numbered the same as in Jack Parsell's Tri-State Corners guide. There are two tri-points associated with the District of Columbia and to distinguish these I have labelled them 32N and 32S for the northern and southern points.

Key to Column Headings

States = The standard two character postal abbreviation for the three states. Tri-Point Name = The name of the benchmark at the tri-point. If no BM name can be found then a PXXXX ft. is assigned from the elevation at the tri-point. If PXXXX m. is shown then the topo map is metric. Topo Map (7.5 min.) = The topo map the tri-point is on. Maps with an asterisk after the name are 7.5 X 15 min. BM Name = The actual name stamped on the benchmark which appears on the USGS datasheet. YR = The year the BM was first placed. PID = The Permanent Identifier used by the USGS to identify benchmarks. ALT PID = The PID of one or more benchmarks either at the tri-point or nearby. Sometimes these are from old surveys where the position is now inaccurate after use of modern measurements.