Have signed centre-back Kyle Cameron, 24, on a free transfer from play-off finalists Torquay United.
Manager Ian Burchnall has described the signing as a ‘big coup’ for the Magpies.
How we rated each Chesterfield player in win against Aldershot Town
The big talking points from Chesterfield's first win of season as Kabongo Tshimanga returns ahead of Wrexham and Notts County clashes
'Bitter pill to swallow' - Aldershot Town boss 'bitterly disappointed' at Chesterfield defeat
Chesterfield were 'worthy winners' against Aldershot Town
Chesterfield re-sign former Notts County goalkeeper who has recently been playing European football
However, one of County’s main men from last season, midfielder Jake Reeves, has left the club to link up with Stevenage in League Two.
As well as losing Cameron to Notts, the Gulls will also have to do without goalkeeper Lucas Covolan who has joined League Two Port Vale.
Covolan, 30, scored a dramatic 95th minute equaliser against Hartlepool United in the play-off final to send the match to extra-time. He also saved two penalties in the shootout but still ended up on the losing team.
The Brazilian has signed a two-year contract at Vale.
King’s Lynn Town
Have sold talented young midfielder Sonny Carey to newly-promoted Championship side Blackpool.
The 20-year-old scored six goals, including in both games against Chesterfield, in 46 appearances last season.
He joins the Tangerines on a three-year deal.
Striker Danilo Orsi, 25, who scored 19 goals in 39 appearances last season, has joined League Two Harrogate Town.
Orsi was named Manager’s Player of the Year and Supporter’s Player of the Year award for Maidenhead.
The newly-relegated Blues have brought in experienced midfielder Abu Ogogo.
The 31-year-old, who has made more than 450 appearances in his career so far, has spent the last two-and-a-half years at Bristol Rovers.
Southend have also signed defender Josh Coulson, midfielders James Dunne and Jack Bridge and well-known goalscorer Rhys Murphy from Yeovil Town.