What we know
Post office 1881-1883, mail to Elbert, on the D&NO line south of Elbert; Scott dates it 1881.
Where it was
'Clermont 1881': Scott, Historic Trail Map of the Denver 1x2 Quadrangle (USGS I-2639, 1999, S-0106), symbol read from the reprojected sheet (good to a few hundred feet). Place Names of Colorado: Sec. 25, T10S R65W, 'Site 2. Rural Post Office 1881-1883. 6 mi W of Sidney. 9 mi SW of Elbert.'; this point is 0.82 mile from that section's center.
Read from Glenn R. Scott's USGS historic trail map of 1999 and confirmed by a second, independent source.
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.