Established in 1982, the MISL is a League devoted to the enjoyment, recreation, and competition for its players, umpires, and spectators.

Sanctioned by the USSSA, the MISL is a competitive league that places teams in a 2 division format. The best established teams play in the A Division and newer or building teams play in the B Division. Divisions are defined by the previous seasons final outcome. The B Division regular season first place team and/or Champion will move into the A Division. The last place finisher(s) in the A Division will move into the B Division. If additional teams are required in the A Division, the final regular season standings from the B Division will dictate teams involved in further re-alignment.

Games are played on Sundays, from 9:00 am until 1:00 pm. Schedules are arranged so that teams play doubleheaders every other week. The season typically runs from the beginning of May thru mid August. Playoffs begin at the end of August and finish with the Championships in mid September.

The preseason schedule is as follows:
1. The league commission and team managers meet to discuss league issues and ideas at the initial pre-season meeting in February.
2. Official league rules for the upcoming season are established at the second pre-season meeting in March.
3. Team Rosters and League Fees (to include, MISL, USSSA, Insurance and Softball fees) are due at the final pre-season meeting in April. Additional team expenses such as game umpire’s fee (payable prior to each game) and team equipment, such as bats, jerseys, scorebooks, etc. are supplied by team at team’s expense.

The MISL has two team classifications listed below which dictates fee totals paid by each team.
A. Marlboro Team 1. Classified as having more than 70% Marlboro residents on the official team roster. 2. Six (6) player maximum for out of town players on 20 man roster.
B. Out-of-Town Team 1. Classified as having less than 70% Marlboro residents on the official team roster. 2. No maximum for out of town players on 20 man roster