Picking the best in-state rivalry is easy. Alabama-Auburn. Picking the top 10 in-state rivalries is a little more difficult.
Lots of factors involved. Are they arch-rivals? Do they usually play at the end of the season? How many of their games have determined championships? How competitive has the series been? How competitive is the series now?
Here's our list, with one explanation. USC-UCLA and Stanford-Cal were not considered. They strike us as city rivals, not state rivals:
Series: Bama leads 41-34-1.
Name: Iron Bowl
History: The series was suspended in 1907 in a dispute over per diem for visiting teams and wasn't resumed until 1948.
Conference ramifications: Bama beat Auburn in defacto SEC title games in 1953, 1965, 1971 and 1979. The bitter foes met with division titles on the line in 1989 (Auburn), 1994 (Bama) and 2005 (Auburn).
National impact: 22 times both schools have finished a season ranked, including seven years when both were in the top 10 – 1963, 1972, 1974, 1986, 1989, 1994 and 2010.
Used to be…: Birmingham was the annual home for the Iron Bowl. Not until 1989 did Auburn host. The game was played in Tuscaloosa in 2000 for the first time in 99 years.
This year: No. 2-ranked Alabama, 10-1, hosts 3-8 Auburn on Saturday.
2. FLORIDA STATE-FLORIDA
Series: Florida leads 33-21-2
History: Didn't start until 1958 (FSU had been a girls school into the 1940s). Florida agreed to play by legislative threat.
Conference ramifications: Never in the same conference
National impact: Florida beat Florida State in 1996 national title. 20 times both teams have finished ranked in the polls, including eight times with both in the top 10.
Used to be…: The biggest game annually in college football. From 1993 through 1999, the schools combined for three national titles. Both finished in the top 10 every season from 1991 through 1998.
This year: Fourth-ranked Florida plays at No. 10 Florida State on Saturday in a battle of 10-1 teams.
3. CLEMSON-SOUTH CAROLINA
Series: Clemson leads 65-40-4
Name: Palmetto Bowl
History: From 1896-1959, the game was played on the state fairgrounds of Columbia, the home city of the Gamecocks.
It moved to the campuses in 1960.
Conference ramifications: The rivals shared a conference from 1922 through 1970 but played only once for the title. Clemson beat South Carolina in 1967 for the ACC crown.
National impact: Four times both finished ranked, but never both in the top 10.
Used to be…: When this game was played on the fairgrounds, it was played on a Thursday in October and referred to as Big Thursday. It moved to the season finale in 1962.
This year: 11th-ranked Clemson, 10-1, hosts No. 12 South Carolina, 9-2, on Saturday.
4. OKLAHOMA STATE-OKLAHOMA
Series: OU leads 82-17-7
Name: Bedlam Series
History: In the 1940s, OU tried to get the game moved permanently to Norman.
Conference ramifications: Weren't together in a league until 1960. OSU's win in 1976 helped forge a three-way tie for the Big Eight title with OU and Colorado. In 1984 and 2010, OU won games that decided the league or division title. OSU did the same in 2011.
National impact: Eight times both teams have finished ranked, with the 1984 shootout (No. 2 vs. No. 3) the highlight.
Used to be…: Incredibly one-sided. Between 1945 and 1995, OSU won three times.
This year: 13th-ranked OU (8-2) hosts No. 21 OSU (7-3) on Saturday with at least a share of the Big 12 title still possible for both.