Willimantic police arrested three Eastern Connecticut State University students on Saturday night after getting complaints that their Halloween party had gotten out of control.
Police responded to the house on Ash Street after a neighbor complained that the party had been going on all night and was out of control, police said.
When officers arrived, they found around 50 people in costume outside the house and said some were in the road.
While clearing the scene, police found another 100 to 150 people inside.
Police arrested three ECSU students for hosting the party and charged them with second-degree breach of peace.
A fourth male who was also at the house was arrested after a brief encounter with a female patrol officer and charged with interfering with police.