Entrepreneur and Portland co-founder Francis W. Pettygrove was born in Calais, Maine, in 1812. After being educated in his home town, Pettygrove entered into a number of independent business activities in his native New England. In 1842, he contracted with a mercantile company to ship a stock of general merchandise to distant Oregon. Then, with his wife Sophia Roland Pettygrove, he traveled by way of the Sandwich Islands (present-day Hawaii) to Fort Vancouver. There he arranged with the Hudson's Bay Company for a schooner to transport the merchandise up the Willamette River to his destination—Oregon City. After selling his stock of goods, Pettygrove built a warehouse in Oregon City and set up a business trading in fur and wheat.

At the same time Pettygrove was establishing his business ventures, lawyer and Oregon City mayor Asa Lovejoy had gained a half-interest in a 640 acre tract of land along the Willamette River twelve miles downstream from Oregon City, referred to as "The Clearing." In early 1844, Francis Pettygrove purchased the other half-interest from Lovejoy's partner William Overton for fifty dollars' worth of goods. Pettygrove and Lovejoy worked diligently through 1844-45 to improve the site. After trees and debris were cleared near the foot of present-day SW Washington Street, a small log cabin was built for use as a store and warehouse.

In 1845, Lovejoy and Pettygrove hired itinerant surveyor Thomas A. Brown to plat the Portland townsite in sixteen 200-foot-square blocks. The two owners, however, could not reach a consensus on the naming of the townsite. Lovejoy favored naming it after his hometown of Boston, while Pettygrove preferred Portland after the shipping city in his home state of Maine. When a copper penny was flipped in 1845 to settle the name dispute, Pettygrove's Portland won two out of the three tosses.

Lovejoy did not long retain his half of the townsite and in September 1848, Pettygrove began selling off his share. After both men had sold their interests, a legal dispute arose between the two regarding the land immediately adjoining the Willamette River. According to Lovejoy, both he and Pettygrove agreed that the riverside land would be retained for public use. Pettygrove, however, having built the first building on the levee, denied the claim that they ever intended public ownership. The case went to court in 1853 and the levee was eventually deemed private.

In 1851, Pettygrove joined with businessman L.B. Hastings with the idea of establishing a new town at the entrance to the Puget Sound. After building a schooner and obtaining goods and supplies, Pettygrove and Hastings sailed north and founded the city of Port Townsend. While the two men spent the remainder of their lives attempting to build a metropolis that would dwarf Portland, the Washington city would never rival Portland in size or commercial significance. Francis Pettygrove died in Port Townsend in 1887.