The 28-year-old Republic of Ireland international is into his third season with the Rams after joining from Coventry City in 2012.
"The new contract should be signed in the coming days and we are delighted with that," McClaren said after Saturday's 2-2 draw against Cardiff City.
"I thought Richard was excellent again in the Cardiff game. He is valuable to us on and off the field as our leader.
"The team is good at the moment, the future is bright and we have got all of our best players under long-term contracts. That is important to us."
It is expected that Keogh, whose current deal expires at the end of the season, will sign a three-year contract until the summer of 2017.