Utah Lake near Provo, Utah contains a healthy population of good sized Carp.  I know this from reports of anglers that have caught them accidentally while fishing for Catfish.  The lake is 96,000 acres in size and is located at an elevation of 4500 feet.

From Utah State Parks:

DIRECTIONS:
Travel south on 1-15 to Provo Center Street exit 268B. Travel west on Center Street 2 miles to the end of Center Street. Park is located at end of road. 

INFORMATION: 

At Utah Lake you can fish year-round for channel catfish, walleye, white bass, black bass and several different species of panfish in Utah's largest fresh water lake. The state park provides major access to the 96,600-acre lake for power boating, sailing, canoeing or kayaking. An Olympic-sized ice rink hosts ice skaters from November through March.

Utah Lake State Park is five miles west of Provo just off Interstate 15. Facilities include four boat launching ramps, sheltered 30-acre marina, 78 seasonal/transient boat slips, modern rest rooms, showers, 71 campsites, a fishing area for the disabled, and sewage disposal and fish cleaning stations.

Park Information:

Acres - 308 
Elevation - 4,500 ft. 
Park Open - All Year 
Reservations Accepted - 4/15-10/15 
Stay Limit - 14 Days 
Total Units - 73 
RV Trailer Sites - 73 
Maximum RV Length - 40 ft. 
Tent Sites 
Camping Fee - $10 & $12 
Group Camping 
Day-use Fee - $5 
Visitor Center/Museum - Hours Vary 
Picnicking 
Drinking Water 
Modern Rest Rooms 
Showers 
Waste Disposal 
Boating 
Fishing 
Swimming 
Winter Activities - Fishing, ice skating 

For updated information regarding facilities for the physically challenged, contact the park. 

Utah Lake State Park
4400 West Center Street
Provo, Utah 84601-9715
(801) 375-0731