It rises in eastern Butler County and flows southwest, through the Lake Oneida reservoir and past Butler, then WNW in a meandering course past Harmony and Zelionople. It receives Slippery Rock Creek from the northwest near Ellwood City, then joins the Beaver west of Ellwood City, approximately 3 mi (5 km) further downstream.
The creek is a very popular kayaking place. Many people enter the water at the bridge at old Route 96.
The creek is formed in Franklin County, Pennsylvania at the confluence of the West and East Branches of Antietam Creek about 2.3 miles (3.7 km) south of Waynesboro, Pennsylvania.
The creek is noted for numerous well preserved stone arch bridges dating to the 19th Century that still traverse the creek, the most famous of which is the 125 foot (38 meter) long Burnside Bridge in the Antietam National Battlefield.
The creek was a major topographic feature during the Battle of Antietam (called the Battle of Sharpsburg in the American South) fought on September 17, 1862, near Sharpsburg, Maryland.
ConnoquenessingCreek is a tributary of the Beaver River, approximately 50 mi (80 km) long, in western Pennsylvania in the United States.
It receives Slippery Rock Creek from the northwest near Ellwood City, then joins the Beaver west of Ellwood City, approximately 3 mi (5 km) further downstream.