Welcome to Lake McConaughy! Nebraska's largest lake with over 100 miles of shoreline and great fishing. At full storage, Lake Mac is 20 miles long, 4 miles wide and 142 feet deep at the dam. Built on th edge of the Nebraska Sandhills, Lake Mac offers natural white sandy beaches, excellent fishing, boating, camping and all types of outdoor recreation. Check it out at ilovelakemac.com.