United States Census Bureau bulletin on Utah censuses 1850-1900 records State population by decade.
"Census Bulletin: Population of Utah by Counties and Minor Civil Division," census.gov, accessed December 18, 2023
1900 ---------------------------------------- 276, 749
1890 ---------------------------------------- 207, 905
1880 ---------------------------------------- 143, 063
1870 ---------------------------------------- 86, 786
1860 ---------------------------------------- 40,273
1850 ---------------------------------------- 11, 380