Jake Layman added 16 points and had a career-high six assists for the Terrapins. Maryland, which is competing in the Big 10 this season after 61 years in the ACC, won its 38th consecutive home opener.
Nolan Long led Wagner with 13 points. The Seahawks were held to just 18 of 65 from the field (27.7 percent).
Maryland started the game on a 15-3 run with Richaud Pack making both of his 3-point attempts. Trimble's second 3-pointer and layup by Dion Wiley increased the lead to 28-11 with 7:17 left in the first half.
Maryland steadily pulled away and a dunk by Layman in the final minute provided a 43-17 margin at the half. The Terps shot 14 of 27 (52 percent) from the field, including 6 of 10 from 3-point range, in the first half.
The second half was not much better for Wagner as a dunk and ensuing free throw by freshman Michal Cekovsky boosted the margin to 58-24 with 13:02 remaining.
Maryland: Maryland forward Dez Wells, who was an All-ACC Third Team pick last season, fell hard to the court late in the first half and suffered a left ankle sprain. Wells was able to return to the game and played most of the second half.
Wagner: Marcus Burton, the Seahawks' leading returning scorer, will have to play an even bigger role this season for the Seahawks, who lost four starters to graduation. Burton averaged 11 points last year and was the only player in the NEC to average double figures without starting a game. He finished with seven points against Maryland.
Wagner visits Columbia on Tuesday.
Maryland hosts Central Connecticut State on Monday.