Just one, they made a movie about it called The Express
One national championship
They have won two: a club football national title in 1973 and I-AA mid-major national championship in 2003.
The Fightin' Blue Hens have won six national titles in their 116-year history - 1946 (AP College Div.), 1963 (UPI College Div.), 1971 (AP/UPI College Div.), 1972 (AP/UPI College Div.), 1979 (D-II)...
5. In 1914, 1919, 1923, 1927, & 1951.