Whitlow 36, made over 130 appearances for the Trotters between 1997 and 2003 following his move from Leicester City, the last of which came in last seasons home encounter with Middlesbrough at the Reebok Stadium when a 2-0 victory was enough to secure Bolton's Premiership status for another season.
Despite being offered a new one year deal on reduced terms the veteran Whitlow decided to step down a division and he eventually joined Sheffield United following a successful trial but has been unable to cement a regular place in the Blades first team this season making just 20 appearances in South Yorkshire.
The left-back or centre-back will now link up with ex-Leicester team mate Gary Mills who is the manager of recently relegated County and his experience is expected to be invaluable as the Magpies hope to bounce back to the Second Division at the first attempt.
Mills was unsurprisingly happy to add the experience of "Whits" to his squad and confirmed the move for the former Leeds man will not be the last of the new faces to arrive in Nottingham this summer with ex-England ace Des Walker also being targeted to move from arch rivals Forest.
"Mike Whitlow will be my first signing of the summer, I have that one in the bag. Mike is the type of player who will help us succeed next season" Mills said
Another ex-Wanderer is also set to pledge his future elswhere next season as Burnley winger Glen Little, on loan to Bolton earlier this season, has agreed in principle to a Bosman move to Reading.