On December 21, 1620, the first landing party arrived at the site of what would become the settlement of Plymouth. Plans to immediately begin building houses, however, were delayed by inclement weather until December 23. As the building progressed, twenty men always remained ashore for security purposes, while the rest of the work crews returned each night to the Mayflower. Women, children, and the infirm remained on board the Mayflower; many had not left the ship for six months. The first structure, a "common house" of wattle and daub, took two weeks to complete in the harsh New England winter. In the following weeks, the rest of the settlement slowly took shape. The living and working structures were built on the relatively flat top of Cole's Hill, and a wooden platform was constructed to support the cannon that would defend the settlement from nearby Fort Hill.
Many of the able-bodied men were too infirm to work, and some died of their illnesses. Thus, only seven residences (of a planned nineteen) and four common houses were constructed during the first winter.
During the first winter in the New World, the Mayflower colonists suffered greatly from diseases like scurvy, lack of shelter and general conditions onboard ship. 45 of the 102 emigrants died the first winter and were buried on Cole's Hill. Additional deaths during the first year meant that only 53 people were alive in November 1621 to celebrate the first Thanksgiving. Of the 18 adult women, 13 died the first winter while another died in May. Only four adult women were left alive for the Thanksgiving.