No injuries were reported as crews worked much of the day to extinguish the blaze.
A Hope Township barn was destroyed in a fire Saturday.
Crews from several municipalities were called at 9:42 a.m. to the blaze at 496 Delaware Road, and some were still on scene almost six hours later, according to New Jersey State Police in the Hope barracks.
No injuries were reported. The investigation is ongoing, police said.
Some roads in the area were closed as fire crews worked to extinguish the blaze.
Steve Novak may be reached at snovak@lehighvalleylive.com. Follow him on Twitter @type2supernovak. Find lehighvalleylive.com on Facebook.