The answer is 2005
Zora Clevenger
The 2008 Boise State football team ended up with a 12-1 record and were WAC champions for the 6th season in 7. They went undefeated in Conference play and the rest of the 'regular season'. Their only loss was to TCU, 17-16, in the Poinsettia Bowl.
The 1948 Cleveland Browns of the All American Football Conference had a regular season record of 14-0 and won the AAFC championship game over the Buffalo Bills to become the first professional football team to go through an entire season, including playoffs, undefeated.
Arsenal that was in 2005
There are no more undefeated teams left in the National Football League during the 2010-2011 season
Packers! They are undefeated
Miami dolphins
Rutgers
The Tide won all 10 of their regular season games but lost the Orange Bowl to Texas, 21-17, to end the season 10-1. They were named 1964 National Champions by the Associated Press and United Press International.
Arsenal went undefeated in the 2003-2004 premier league season
The 72' Miami Dolphins went undefeated in a 14 game regular season and then went on to win the Superbowl. The 85' Chicago Bears were in line for an undefeated season and suffered their only loss to.... the Miami Dolphins! The 2007 New England Patriots went undefeated during the regular season, the only team to do so with a 16 game schedule, and would eventually lose to the New York Giants in the Superbowl.
its only been one season the pats did it in 07 but lost in the super bowl