Courtesy of "Life in Summit County"

4,000 B.C. - The original locals
Native Ute tribes settled the area entering the basin primarily from the north along the Williams Fork Mountains. Archeological digs have revealed campsites near Keystone and Copper Mountain that are more than 6,000 years old. The Ute were nomadic, hunting tribes who followed the migration of the big game. While buffalo were plentiful in nearby Middle Park, rarely did the prized animals venture into the higher areas of Summit Park. ("Park" was the term used by the settlers describing the level, fertile lands between the mountain ranges.) Elk and deer were plentiful in the area, as well as prized fur animals: beaver, fox and marten.
Unlike the aggressive Arapaho tribes of the Front Range, the mountain Ute tribes were peaceful and accepting of the influx of white men. But the pressure created by the trappers, explorers and miners diminished their hunting grounds and the Utes' nomadic instincts prevailed. Once the miners began to establish towns the Utes expressed little interest in staying, and moved on to the quieter areas of southern Colorado.

1805 - Pike Reaches the Divide
Zebulon Pike was sent to map the area recently acquired in the Louisiana Purchase. Although Pike's successes are widely disputed, a primary goal was to discover the source of the Arkansas River. He came to the Summit from the south, following the Arkansas and South Platte River. While he didn't achieve his intended goal, by inadvertently following the Middle Fork of the South Platte he did manage to map the Mosquito Range at the southern part of the county and major portions of the Continental Divide.

1848 - Colorado Territory
The land west of the Continental Divide was held by Mexico until the Mexican War, which extended the territory through Utah, Nevada and California.

1859 - Gold Fever
Gold was discovered in Denver's Cherry Creek. The rush ensued by following the source of the free running gold up Clear Creek to Idaho Springs. It didn't take long for the heartiest miners to cross the high divide into the Summit Basin. Gold was abundant in the Summit Park and ramshackle towns sprang up like weeds. Montezuma, Breckenridge and Kokomo were hot spots of mining and a county was born.

1861 - i before e except as in Breckenridge
General George E. Spencer established the town of "Breckinridge" for President James Buchanan's Vice President, John Cabell Breckinridge. When it was discovered that Breckinridge's Civil War sympathies were with the South, the embarrassed little town discretely changed the spelling of its name to "Breckenridge," changing an "i" to an "e."

1876 - Statehood
Colorado is granted statehood by President Ulysses S. Grant.

1891 - No Man's Land
An error was discovered in the drawing of two important U.S. annexation maps: one map covered the Continental Divide to the eastern slope, and the other from the Continental Divide to the western slope. Where the maps were supposed to meet, a 40-mile strip of land from Hoosier Pass to Slate Creek through central Summit County had been omitted. This ungoverned void gave the good-humored residents of the area the idea that their County Seat could become its own Kingdom. Never missing the opportunity for a party, the "Kingdom of Breckenridge" established No Man's Land Day.