You can park your car in the Fort Baldwin State Park lot. It's only a short distance (<0.10 miles) to the cache from here. There's no specific path to the location so explore different ways to the spot.
This area has a very special history in the United States. Native Americans once dug clams and fished here, leaving arrow heads and other artifacts. It was also the first English Colony in New England, founded in the same year as Jamestown, August 29th, 1607.
Before heading to this cache: Look for and bring an old found treasure (beach glass, shells, special rocks, man made relic, etc). The cache is a container about the size of a small bread box, come with your loot ready to make a trade!
History lesson from Wikipedia:
The Popham Colony (also known as the Sagadahoc Colony) was a short-lived English colonial settlement in North America that was founded in 1607 and located in the present-day town of Phippsburg, Maine near the mouth of the Kennebec River by the proprietary Virginia Company of Plymouth. It was founded a few months after, and in the same year as, its more successful rival, the colony at Jamestown, which was established on May 4, 1607 by the Virginia Company of London in present-day James City County, Virginia.
The Popham Colony was the first colony in the region that would eventually become known as New England, coming five years after a short encampment on Cuttyhunk. The colony was abandoned after only one year, apparently more due to family changes in the leadership ranks than lack of success in the New World. The loss of life of the colonists in 1607 and 1608 at Popham was far lower than that experienced at Jamestown.
The first ship built by the English in the New World was completed during the year of the Popham Colony and was sailed back across the Atlantic Ocean to England. The pinnace, named Virginia of Sagadahoc, was apparently quite seaworthy, and crossed the Atlantic again successfully in 1609 as part of Sir Christopher Newport's nine vessel Third Supply mission to Jamestown. The tiny Virginia survived a massive three day storm en route which was thought to have been a hurricane and which wrecked the mission's large new flagship Sea Venture on Bermuda.
The exact site of the Popham Colony was lost until its rediscovery in 1994. Much of this historical location is now part of Maine's Popham Beach State Park, and is listed on the National Register of Historic Places.