Already the country's leading run scorer, Jennings reached 200 with his 31st boundary off the final ball of the day as Durham closed on 393-9.
Surrey-bound Scott Borthwick was Durham's next highest scorer with 38.
South African Jennings, whose career-best 221 not out came against Yorkshire in June, gave just one chance on 118 in his record seventh ton of the summer.
He was put down by Kumar Sangakkara off in-form Surrey fast bowler Mark Footitt, who ended the day with 4-88.
Having got away with that one, Jennings had moved on to 1,510 Championship runs for the season by day's end, putting him in reach of the Durham county record for a season, set by former skipper Michael di Venuto (1.654) in 2009.
It also put Durham, still needing points to stay up in Division One, within seven runs of a fifth batting point. Jennings has so far put on 23 with Graham Onions, following stands of 79 for the eighth wicket with Brydon Carse (32) and 61 for the ninth with England paceman Mark Wood (28).
Durham have not lost in their last seven Championship meetings with Saturday's One-Day Cup finalists Surrey, who lost by an innings on both of their last two trips to Durham.
Jennings' seventh first-class century of the summer made him the first Durham batsman to achieve that feat, surpassing the six made by Di Venuto and Paul Collingwood in 2005.
it was also his sixth at the Riverside, following his knocks against Yorkshire (beating his 185 on the first day in that game), 171 against Notts, 129 against Hampshire, and his pair of tons against Somerset.
His only century away from home was his matchwinning 113 against Warwickshire at Edgbaston in May.
Keaton Jennings' second double century of the summer helped Durham bat all day against Surrey at Chester-le-Street.