Judge, who began his career at Rovers, has signed a three-year contract while Taylor and Eastwood have put pen to paper on two-year deals.
Irishman Judge, 24, came through the youth ranks at Blackburn and was on the fringes of the first team but made only two senior appearances for Rovers before joining Notts County in a permanent move in January 2011 after a loan spell at Meadow Lane.
An instant hit with the Magpies, Judge won the player of the year award in his first full season and followed that up by being named in the PFA League One team of the year for the 2012/13 campaign.
Taylor returns to his native north west after a year with Millwall. The 26-year-old started his professional career at his hometown club Oldham, enjoying a seven-year spell with the Latics and making over 250 appearances and scoring 33 goals.
He joined Millwall on a one-year deal last summer and went on to play a huge part in the Lions' charge to the FA Cup semi-finals.
Former Huddersfield and Halifax keeper Eastwood arrives from Portsmouth where he worked under Rovers' goalkeeping coach John Keeley.
Eastwood has completed formalities on his move, while Judge and Taylor will officially become Blackburn players on July 1.