Armstrong House makes up the western-most section of the Mission Park dormitory. Built in the 1970's and upgraded in the 1990's, Mission Park takes its name from the part of campus where, in 1806, five Williams students gathered in the then-maple grove on a warm summer day to discuss their interest in spreading Christianity. When a sudden lightning storm interrupted their discussion, they took shelter in a nearby haystack (check out the Haystack Monument on your way to the building!), huddling and praying for foreign missionaries.

Winner of an architectural award (yes, it's true), Mission Park and the four houses within boast excellent but oddly-angled single rooms, horizontal entries, large lounges with flat-screen TVs, and a huge dining hall. Above the dining hall are lounges with pool tables and a kitchen. Mission Park houses half of the First-year Class and is made up of primarily single rooms.