What we know
First settled July 10, 1860 (Crofutt); PO March 27, 1865 at G. W. Redman's (SW1/4 Sec. 27), kept by J. F. Gile in 1877, moved to Jacob Geiger's in May 1885, closed July 1885. Divide Grange No. 53 met at the schoolhouse. Cemetery a mile north (39.159, -104.768). Place Names of Colorado's Sec. 1 is the Pratt farm, not Spring Valley.
Where it was
1994 GPS readings of the store foundation (Larkspur binder, Spring Valley Book 1 p. 168), W1/2 NW, Sec. 27, T10S R66W, 40 m from GNIS's Spring Valley School. The 1877 post office site report puts the office in the NE1/4 of the same section (see 'Gile's ranch').
Placed from a written description, such as a land section, a distance from a landmark or an old survey note.
Sources
Sources are named in the text above. Numbers such as S-0080 refer to our source list. Most newspaper quotations were read in the Colorado Historic Newspapers Collection. Long quotations from recent books are shortened here.