San Juan County, New Mexico (Extinct)
The original San Juan was a county of New Mexico from 1861 to 1862. Later a different county was created with the same name, which exists to the present.
12 Jan 1861 - SAN JUAN county (original, extinct) created by New Mexico Territory from TAOS county, New Mexico. It stretched west to the California border, including lands in present day Arizona and Nevada. 
18 Jan 1862 - SAN JUAN county (original, extinct) lost all territory to TAOS county, New Mexico when the law creating SAN JUAN was repealed. SAN JUAN was eliminated.  Look for records of San Juan county (extinct) in Taos County, New Mexico.
- N.M. Terr. Laws 1860-1861, 10th assy. /p. 16
- N.M. Terr. Laws 1861-1862, 11th assy. /p. 16