Rebounding from a 30-point loss to No. 1 Michigan State just three days earlier, the Terrapins (14-4, 3-2) used a second-half surge to secure their eighth win in nine games.
Iowa head coach Fran McCaffrey was issued two technical fouls with 45 seconds remaing before halftime, giving Cowan Jr. the chance to connect on on three of four free throws for a 48-44 edge at the half. The Hawkeyes (9-9, 0-5) hung in there without McCaffery, but faded in the latter stage of their third game in six days.
Isaiah Moss led Iowa with a career-high 25 points and Bohannon had 17.
After Bohannon hit a 3-pointer to put Iowa up 64-61, a dunk by Fernando sparked a 19-2 run that put the Terrapins ahead for good. Cowan contributed seven points to the spree and Darryl Morsell chipped in with three baskets.
In the closing minutes, the 6-foot-10 Fernando punctuated the victory with a one-handed jam off an alley-oop pass from Cowan, then added a free throw.
Six players scored in double figures for the Terrapins. Morsell had 14 points, Michal Cekovsky scored 13 on 5-for-5 shooting, Kevin Huerter had 12 and Dion Wiley added 10 before leaving with an injury.
Maryland overcame an early deficit and outscored Iowa 13-5 at the foul line in taking a 48-44 halftime lead.
All five starters scored in the opening minutes for the Hawkeyes, who bolted in front 17-7.
It was 24-17 before Wiley and Cekovsky accounted for all the points in a 12-0 run.
Maryland hit 10 straight shots from the floor during the first half, and the 48 points were a season high over the opening 20 minutes.
Maryland will hit the road Thursday night against the Buckeyes, who stunned Michigan State 80-64 on Sunday.