Several fights broke out after a group of about 200 people congregated at State Street and Frances Street in downtown Madison after 2 a.m. Saturday, according to police.
A dozen officers responded, and pepper spray was used to disperse a group fighting.
Police said several arrests were made. One man was arrested after striking an officer in the head and chest, according to police. The officer was not seriously injured.
Theodore D. Taylor, 22, was arrested on suspicion of disorderly conduct, resisting arrest, battery to a police officer and a probation violation.