A Maine Forest Service ranger is investigating the cause of a fire at Sebago Lake State Park which started Sunday night and burned into Monday morning.

The fire occurred in the day use area of the park, according to Forest Ranger John Leavitt, adding that eyewitnesses saw a group of juveniles Sunday night in the area of the park where the fire ignited. Leavitt said the Forest Service is hoping to contact them.

The Casco Fire Department received a call around 9 a.m. Monday, said Fire Chief John Small. When they arrived, park rangers were already working to put the fire out. It took firefighters from Casco, Naples, Raymond, and Otisfield about five hours to suppress the fire that burned more than one acre.

Sebago Lake State Park sits on a total of 1,400 acres in Casco. One of the first state parks in Maine, it includes a 250-site campground. Leavitt said the fire is unlikely to make a big impact on the park.

The fire in Casco was not an isolated incident. “We’ve seen our fire activity in the past few days increase as weather gets warmer and drier and breezy,” said Leavitt on Wednesday.