The 37-year-old died from an “apparent self-inflicted gunshot wound“, Arkansas sheriff Marty Moss said.
Her death comes weeks after that of her boyfriend and father of one of her two sons, record producer David Wilson, whose death is being investigated.
The singer had attempted to take her own life twice before and was known to have problems with substance abuse.
The Cleburne County Sheriff’s Office said McCready’s body would be taken to the Arkansas State Crime Lab for an autopsy, adding that “the matter will be fully investigated.”
She recorded five studio albums, and scored 12 hits on the US country music charts, including ”Ten Thousand Angels’ and ‘Guys Do It All The Time’.
Her sole UK chart appearance came in 1998, when ‘Oh Romeo’ reached number 41.
Her fifth album, ‘I’m Still Here’, was released in 2010.