In 1872, a group of soldiers from Silver City, New Mexico, lead by Captain Chase were seeking renegade Apaches, in the group were Jim and Bob Metcalf. While passing through the canyon the Metcalfs noticed rich copper deposits in the walls close to the present day town of Clifton and Morenci. The troops never found the Apaches and returned to Silver City. The Metcalf brother later returned to prospect and staked a claim where they located rich copper deposits. The remoteness of the area and the ever present threat of Indian attacks meant that developing these resources would require large sums of money. Henry Lesinsky, a successful Jewish merchant of Las Cruces and Silver City, New Mexico, decided to invest as a partner of Robert Metcalf, one of the original prospectors of the Longfellow claim. Lesinsky recruited miners from Mexico to do the smelting of copper ore in this new enterprise. Thus, was born the Longfellow Copper Mining Company. After several rather unsuccessful attempts, a crude, but workable smelter (three mud and rock furnaces fired by mesquite charcoal and hand bellows) was built between the confluence of Chase Creek and the San Francisco River. A small settlement of miners developed near the city (a state census record for 1874 shows a population of 132). From that day to the present, the vast majority of people from Clifton, Morenci and Duncan have depended on the mining industry for their livelihood.

Three large copper mining companies, Arizona Copper Mining Company, Detroit Copper Mining Company (Phelps Dodge) and Shannon Copper Mining Companies were all operating at once. James Colquhoun, an engineer and General Manager of the Arizona Copper Company (the A.C. Company had bought Lesinsky's property in 1882). Mr. Colquhoun pioneered a plan for concentrating low grade copper and developed the principles of leaching that led to the profitable use of low grade ores.

Clifton has been under the jurisdiction of several counties. In 1872 they were recorded in Prescott, the county seat of Yavapai County. Later the territory was placed under the jurisdiction of Apache County. In 1881 Graham County was created from parts of Apache and Pima counties. Clifton was in the part of Apache County that was ceded to Graham County. The people were glad because now their county seat was only 45 miles away at Solomonville. Being a wild mining town, Clifton was not interested in government or they would have fought for the county seat, because Clifton had far more population than Solomonville. By the turn of the century the people of Clifton began to fight for the establishment of a new county. Clifton and Morenci had a combined population of 10,000 while Safford and Solomonville had about half that number. The people of Clifton-Morenci felt that it was the old story of taxation without representation since most of the county officers were chosen by the political machine at Safford. The Clifton and Morenci mines were paying most of the county's taxes.

In the early 1900's the fight for county division was renewed. The managers of the three mining companies had taken up the fight. The Arizona Copper Company wished to name the county after Mr. Colquhoun, who was the head of the company. The leaders in Morenci wanted the name to be Douglas in honor of Dr. James Douglas, superintendent of the Detroit Copper Company of Morenci. This proposal caused the Clifton leaders to give up their proposed name of Colquhoun and substitute Lincoln instead. They sent John R. Hampton a young, able lawyer who worked for the Shannon Copper Company, to the state legislature. He organized the fight at the territorial capital, which led to the establishment of Greenlee County. The mining companies decided to send a large delegation of local men to Phoenix to lobby for division. In Safford and Solomonville a fight was led by Charles Solomon, a banker, against the county division. When the bill was introduced before the legislature, many farmers and townspeople from Graham County made the trip to Phoenix to lobby against it. The bill was introduced on February 25, 1909 as council bill 94. It passed by a majority of 10 to 1. The bill went to the house where it was passed with an amendment to change the name from Lincoln to Greenlee. This was done to delay the final passage of the bill, the amendment lost by a vote of 5 to 4. Mr. Mills, General Manager of the Detroit Copper Company made a trade with the Safford opponents where the final division would be delayed for two years. This agreement and the assumption of all Graham county debts, which were $146,000, by the new county appeased the Safford delegation. Nearly all opposition ceased and the bill passed the next day by a vote of seven to two in the Council. The bill to create a new county was approved March 10, 1909 by Governor Joseph H. Kibbey. It was one of the smaller counties, being only 120 miles long and 20 miles wide containing 1,037,713 acres. With only four populated towns the new county had a population of about 12,000 to 13,000 people.

Both Clifton and Duncan fought to become the county seat. The citizens of Duncan argued that since Duncan was the county's outlet to the rest of the world, and more accessible to the rest of the world, it should become the County's seat. Clifton argued that it was nearer the geographical center of the county and nearer to the population centers of Morenci and Metcalf. Clifton won the fight and the seat was located there.

Besides the Copper Mines of the Clifton-Morenci-Metcalf area, there are mines in the Duncan District of the Gila Valley. Precious metals have been produced at Ash Peak and from the mines in the mountains east of Duncan. Duncan is considered a farming and ranching area. Ranching on Blue River, Eagle Creek, and the "Frisco" River has added to the County economy since the 1870's. One of the three largest cattle company to operate in Arizona was the Double Circle with ranch headquarters on Eagle Creek.
Source: http://www.co.greenlee.az.us/history.aspx