The Magpies looked to be in danger of dropping straight back down to the Championship until a run of four consecutive victories between March and April helped the club pull away from the bottom three.
Newcastle ended the campaign in 10th place after Sunday's 3-0 thrashing of Chelsea at St James' Park and attention is already turning towards summer transfer plans for manager Rafael Benitez.
Scotland international Ritchie, who arrived from Bournemouth in 2016, put in a stellar performance against the Blues and he is hoping to help the club advance over the years to come.
"I think that the best thing to do is to try and raise the bar each year," he told the club's official website. "As a team, we have to keep building, stick together with the same mentality or if we can improve that, improve it.
"Just improve in small areas - all the small, little, tiny one per cent or two per cent improvements will push this club in the right direction. Hopefully I can be a part of that."