Portland is organized into neighborhoods generally recognized by residents, but they have no legal or political authority. In many cases, city signs identify neighborhoods or intersections (which are often called corners). Most city neighborhoods have a local association, which usually maintains ongoing relations of varying degrees with the city government on issues affecting the neighborhood.
On March 8, 1899, Portland annexed the neighboring city of Deering. Deering neighborhoods now comprise the northern and eastern sections of the city before the merger. Portland's Deering High School was formerly the public high school for Deering.
Following the war, a section of Falmouth called The Neck developed as a commercial port and began to grow rapidly as a shipping center. In 1786, the citizens of Falmouth formed a separate town in Falmouth Neck and named it Portland, after the isle off the coast of Dorset, England.Portland's economy was greatly stressed by the Embargo Act of 1807 (prohibition of trade with the British), which ended in 1809, and the War of 1812, which ended in 1815.
In 1820, Maine became a state with Portland as its capital. In 1832, the capital was moved north to Augusta. In 1851, Maine led the nation by passing the first state law prohibiting the sale of alcohol except for "medicinal, mechanical or manufacturing purposes." The law subsequently became known as the Maine law, as 18 states quickly followed. On June 2, 1855, the Portland Rum Riot occurred.
In 1853, upon completion of the Grand Trunk Railway to Montreal, Portland became the primary ice-free winter seaport for Canadian exports. The Portland Company manufactured more than 600 19th-century steam locomotives. Portland became a 20th-century rail hub as five additional rail lines merged into Portland Terminal Company in 1911. Following nationalization of the Grand Trunk system in 1923, Canadian export traffic was diverted from Portland to Halifax, Nova Scotia, resulting in marked local economic decline. In the 20th century, icebreakers later enabled ships to reach Montreal in winter, drastically reducing Portland's role as a winter port for Canada.
On June 26, 1863, a Confederate raiding party led by Captain Charles Read entered the harbor at Portland and the Battle of Portland Harbor ensued, one of the northernmost battles of the Civil War. The 1866 Great Fire of Portland, Maine, on July 4, 1866, ignited during the Independence Day celebration, destroyed most of the commercial buildings in the city, half the churches and hundreds of homes. More than 10,000 people were left homeless.
By act of the Maine Legislature in 1899, Portland annexed the city of Deering, despite a vote by Deering residents rejecting the annexation, thereby greatly increasing the size of the city and opening areas for development beyond the peninsula.
The construction of The Maine Mall, an indoor shopping center established in the suburb of South Portland, during the 1970s, economically depressed downtown Portland. The trend reversed when tourists and new businesses started revitalizing the old seaport, a part of which is known locally as the Old Port. Since the 1990s, the historically industrial Bayside neighborhood has seen rapid development, including attracting a Whole Foods and Trader Joes supermarkets. Other rapidly developing neighborhoods include the India Street neighborhood near the Ocean Gateway and Munjoy Hill, where many modern condos have been built.  The Maine College of Art has been a revitalizing force downtown, attracting students from around the country. The historic Porteous building on Congress Street was restored by the College.