The 21-year-old has agreed terms on a deal for the 2014/15 campaign.
Spireites boss Paul Cook is hopeful that the defender will prove to be a long-term success at the Proact Stadium.
"Charlie has good potential and we view him as very much one for the future," Cook told his club's official website.
"Having previously signed Ollie Banks from FC United of Manchester, it shows the good work that is being done there to develop young players."
Raglan came through the ranks at Port Vale before spells in non-league football with Hinckley and Nantwich before signing for FC United in 2013.