The Utah Division of the former Denver & Rio Grande Western Railroad (D&RGW) is a rail line that connects Grand Junction, Colorado and Salt Lake City, Utah (formerly Ogden) in the Western United States. It is now incorporated into the Union Pacific Railroad (UP) system as part of the Central Corridor. The modern Union Pacific has split the line into two subdivisions for operational purposes, the Green River Subdivision between Grand Junction and Helper, Utah and the Provo Subdivision from Helper to Salt Lake City. Daily passenger service is provided by Amtrak's California Zephyr; the BNSF Railway and Utah Railway have trackage rights over the line.

The line dates back to the early 1880s, when the predecessors of the D&RGW completed a 3 ft (914 mm) narrow gauge line through the Royal Gorge, over Marshall Pass, through the Black Canyon of the Gunnison, across the Utah desert, and over Soldier Summit. It was rebuilt to standard gauge in 1890, and has since remained a through line, often serving as parts of larger networks including the Gould transcontinental system, Southern Pacific, and now the Union Pacific.

The division also included a number of branch lines, the longest being the Marysvale Branch through the Sevier Valley.

When the Denver & Rio Grande Railway (D&RG) was chartered in 1870, it had the goal of connecting Denver with El Paso, Texas. But when it reached Raton Pass in 1878, it found that the Atchison, Topeka and Santa Fe Railroad had beaten it to the best crossing into New Mexico. After several years of financially draining battle, the two companies came to an agreement in 1880, and the D&RG, under the direction of William J. Palmer, set its sights on Salt Lake City.

In the meantime, the Utah and Pleasant Valley Railway (U&PV) had built a 3-foot (914mm) narrow gauge line from the coal mines in the Pleasant Valley to Provo on the Union Pacific Railroad-controlled Utah Southern Railroad. The company was incorporated on December 11, 1875, under the general laws of Utah by owners of land in the valley. The company began grading in April 1877 and track laying on August 29, 1878, driving the last spike between Pleasant Valley and Springville on November 5, 1879. The short distance in the Utah Valley from Springville to the larger city of Provo, which closely paralleled the Utah Southern, opened in October 1880. Investor Charles W. Scofield of New York, who was already in control of two other narrow gauge mining roads - the Bingham Canyon and Camp Floyd Rail Road since 1873 and the Wasatch and Jordan Valley Railroad since 1875 - acquired the U&PV in October 1878.

The U&PV began at a mine in the Pleasant Valley south of Scofield, heading north along the present Pleasant Valley Subdivision to the Scofield Reservoir. The old grade has been flooded until it leaves the lake to the north, rising to an elevation of 7,967 feet (2,428 m) above sea level before descending, via a pair of switchbacks, to Starvation Creek. The valley of that creek took the railroad to the Spanish Fork Canyon, and the later D&RGW, at Tucker. The remainder of the U&PV is now, for the most part, still operated, as it follows Spanish Fork Canyon into the Utah Valley.

The Central Pacific Coal & Coke Co. Ltd. of London chartered the San Pete Valley Railroad in 1873 to develop its mining properties in Utah. Opened in 1882, the narrow-gauge line ran 30 miles from Nephi to the parent company's coal deposits at Wales, was extended 35 miles to Moroni in 1884, to Manti (43 miles) in 1893, and to Morrison (51 miles) in 1894. The D&RG purchased the railroad in 1907.

Associates of Palmer incorporated the Sevier Valley Railway in Utah on December 7, 1880, with a route paralleling the Union Pacific's lines from the railroad center of Ogden south through Salt Lake City and Provo to Nephi, and then continuing through Salt Creek Canyon and the Sanpete Valley to Salina in the Sevier Valley. There it would split, one line continuing south to the Arizona state line, and the other turning east through Salina Canyon and across the Castle Valley to the Grand (Colorado) River, following it to meet the westward-building D&RG at the Colorado border. To counter this threat to its monopoly, the Union Pacific set up the Utah Southern and Castle Valley Railroad less than two weeks later to extend its Utah Southern through Salina Canyon to the Castle Valley. In another week, when UP workers reached the canyon, the Sevier Valley had already begun grading.