The first land filings were made by Tracy T. Tyler where Kremmling is located in 1865. Hilary Harris, John Himebaugh, the Humphrey family, the Green family and the McQueary family also placed claims for a ranch in 1874. In 1875 land along the Troublesome Creek was claimed by Henry King and Barney Day who was the father of the first European child to be born in Middle Park in July, 1876.
Lewis Gaskill discovered gold in the northern portion of the county and in 1879 a minor gold rush occurred until 1885 when mineral deposits had been depleted. Due to the diminishing gold deposits and the threat of Ute Indians in the area in 1885, the population of Grand County was only 15 people according to US Census information.
The first post office in Grand County was established in Fraser in 1876 by William Cozens.
The first telephone service provided by the Colorado Telephone Company in January, 1904, and the first telephone was installed in the Hot Sulphur Springs courthouse for a fee of $60.00 per year.
Routt National Forest was established in 1905. On July 1, 1908, President Theodore Roosevelt made an executive order creating the Arapaho National Forest from portions of the Medicine Bow, Pikes Peak and Leadville forests.
On July 25, 1921 the Grand River was officially renamed as the Colorado River.