Robinson was a restricted free agent. The team announced his new deal about an hour before the start of free agency on Tuesday.
The 25-year-old Robinson has appeared in 26 games for the Redskins over the past two seasons, with one interception.
He was drafted in the sixth round in 2012 by the San Francisco 49ers.
AP NFL website: www.pro32.ap.org and AP NFL Twitter feed: www.twitter.com/AP-NFL