In the early 1890's, as oil commercialization was becoming big business, the McDonald Oil Field became the highest producing oil field in the world. Its development began in the summer of 1890 when the Royal Gas Co. drilled two wells on the Noble McDonald farm about two miles west of McDonald Borough and one on the Edward McDonald farm on the borough's western edge. After those successes, wells spread rapidly in and around the borough, appearing in parks, empty lots, private yards, and even on church property. From 1890 to 1893 at least 1266 wells were drilled in the McDonald area, with an estimated 100 inside the borough, and from 1893 until 1910 at least another 1000 wells were drilled in the field. The Mathews #1 wells just east of town are still recognized as the two greatest production rate wells in Pennsylvania and the Appalachian Basin. About 10 miles long and three miles wide, covering about 13,000 acres, the field was centered on McDonald Borough and extended northeast from Washington County into Allegheny County. Entirely within Pennsylvania, it became the state's second largest oil field in both geographic size and total production, and its exceptionally high output helped Pennsylvania reach a record yearly production of 31,424,000 barrels, while the field itself produced between 84,000 and 96,000 barrels a day. The McDonald Field continued to support a robust oil industry through the 1960's, and some local wells still pump on a small scale. The old McDonald School bell was cast and installed in the new McDonald School in 1875 by the Chaplin-Fulton Company of Pittsburgh. For nearly 75 years, its ringing called elementary and high school students to class, and with its four illuminated clock faces it also automatically sounded and kept the community informed of the time day and night. Its clear, mellow tone could be heard for miles. The bell bears the names of school board members David Brown, president; John A. McCausland, secretary; William Young, treasurer; Harry Plance, Louis Chambon, and Wayne Woodring, along with the name of the building contractor, J. M. Andrews. When the old school building was expected to be demolished in the early 1970s, the bell and clock were removed from the tower and stored in various places around town in hopes of erecting a new tower, but those plans failed. The bell was ultimately placed in Heritage Park, while the clock was mysteriously misplaced and remains missing. On 4 July 1976, the bell was featured during McDonald's National Bicentennial Celebration and on 31 July 1976 it was mounted in Heritage Park, where it remains a classic piece of McDonald's history.