U.S. Route 27, known as Roane Street in Harriman, runs north-to-south through the city along the base of Walden Ridge.

Harriman's southwestern boundary, which it shares with Rockwood, is located along US-27 about a half-mile south of the road's intersection with I-40.

The city's southeastern boundary runs along Pine Ridge, which overlooks the Kingston Fossil Plant.

Seeking a land venture that could attract industrial and economic development while avoiding the vice-driven pitfalls of late 19th century company towns, Gates and fellow prohibitionists chartered the East Tennessee Land Company in May 1889.

In subsequent months, the company acquired several hundred thousand acres of land around what is now Harriman, including the plantation of Union Army colonel and state senator, Robert K. Byrd.

As a colonel (later general) in the Union Army during the Civil War, he had traveled on foot through the area with his 11th New Hampshire Regiment and camped for several days on the Emory River near the future site of the city.

The city, platted on Christmas Day in 1889, was laid out in a grid pattern that conformed to the Emory's oxbow bend at the base of Walden Ridge.

[14] The initial land auction for Harriman was held in late February 1890, and was attended by over 4,000 prospective buyers from across the nation.

[14] In spite of the East Tennessee Land Company's collapse, Harriman continued to grow, although its growth was very gradual.

The American Temperance University was established in 1894, and operated out of the East Tennessee Land Company's abandoned headquarters.

[11] In 1929, the combination of the stock market crash and a devastating flood of the Emory River wiped out much of the city's industry.

The city got a boost in the 1940s and 1950s from heavy automobile traffic along US-27, which was a primary route connecting the Great Lakes region with Florida before I-75 was completed.

The city, still quaint but clearly different now from its economic heyday, still shows considerable evidence of being a "planned community".