When discussing future sea-level rise in Maine, it is important to consider the shifting of the Maine’s coastline from prehistoric times until the present. Sea-level rise is not just a simple measure of the height of the water; it is the intersection of a dynamic continent with an ever-changing water system. More than 15,000 years ago, the weight of the Laurentide Ice Sheet that covered much of northern North America depressed the continent. With the glacier’s retreat, water rushed in to such an extent that the sea level in this region was 75 meters above what it is today. After the glacier’s retreat, the land rebounded with the coastline receding to 60 meters below today’s level. These extreme fluctuations began to even out around 11,500 years ago, with the shoreline roughly 20 meters below today’s level. Since that time, there has been a measurable increase, with some apparent spikes in recent years.