Prospectors entered what is now Summitt County in 1859, soon after the gold discoveries farther east at Idaho Springs. Breckinridge was founded as a base for miners working rich placer gold deposits discovered along Georgia Gulch. Placer gold mining was soon joined by hard rock mining and hydraulic mining. Gold production decreased in the late 1800s, but revived in 1908 by gold dredging operations along the Blue River and Swan River. The Breckenridge mining district is credited with production of about one million troy ounces of gold. While the gold mines around Breckenridge are no longer worked, some are open to tourist visits. Gravel ridges left by the gold dredges can still be seen along the Blue River and Snake River, and remains of a dredge are still in a pond off the Swan River.

An ambitious grid was platted for the Breckenridge town site, with  Main Street laid out parallel to the Blue River.  Residences developed along Main Street to the north, south, and east of the commercial core.  On the west side of the Blue River industry, inexpensive housing, and a red light district were established. By mid-1861, Breckenridge boasted several stores, hotels, saloons, and a post office.  On October 11, 1861, the Town secured the Denver, Bradford, and Blue River Road Wagon Company connection, ensuring the little gold mining community's future.  Breckenridge's Main Street allowed for ease in turning around freight wagons and became the center of social and athletic activities. 

General George E. Spencer is credited with founding the new mining town, naming it after John Cabell Breckinridge, then Vice President of the U.S. General Spencer was hoping to be awarded a post office for the town, which succeeded. However, when the Civil War broke out, the Vice President became a Confederate General and was convicted of treason by the Senate. The town quietly changed an "I" to an "E" and became Breckenridge ever since.

In December 1961, Rounds and Porter, a Wichita, Kansas company, opened the Breckenridge Ski Area and a new-boom era began.  The Eisenhower Tunnel, on I-70, was completed in 1973, reducing the drive time from Denver to Breckenridge to an hour and a half. As a result of the relatively easy access from Denver, the recreational activities in the high country including bicycling, hiking, golfing, fishing, snowshoeing, and skiing, which increased in popularity. Record numbers of skiers and visitors now visit the Town of Breckenridge and record numbers of vehicles now pass through the Eisenhower tunnel. During the 2001-2002 ski season a record 4,400 vehicles passed through the tunnel in a one-hour period.