The city of Portland, Maine, is the hub city of a metropolitan area in southern Maine, in the United States. The region is commonly known as Greater Portland or the Portland metropolitan area. For statistical purposes, the U.S. federal government defines three different representations of the Portland metropolitan area. The Portland–South Portland–Biddeford, Maine, metropolitan statistical area is a region consisting of three counties in Maine, anchored by the city of Portland and the smaller cities of South Portland and Biddeford. As of the 2010 census, the MSA had a population of 514,098.  A larger combined statistical area (CSA), the Portland–Lewiston–South Portland combined statistical area, is defined as the combination of this metropolitan statistical area (MSA) with the adjacent Lewiston–Auburn MSA. The CSA comprises four counties in southern Maine. The Portland–South Portland metropolitan New England city and town area is defined on the basis of cities and towns rather than entire counties. It consists of most of Cumberland and York counties plus the town of Durham in Androscoggin County.
The Portland–South Portland–Biddeford MSA is defined as consisting of Cumberland, Sagadahoc, and York counties.  Portland, South Portland, and Biddeford are the three largest cities in this area and are defined as principal cities of the MSA. Other cities in the MSA are:
Towns in the three-county MSA are:
Census-designated places in the MSA are:
Ten years earlier, as of the census  of 2000, there were 487,568 people, 196,669 households, and 128,201 families residing within the MSA. The racial makeup of the MSA was 96.49% White, 0.80% African American, 0.27% Native American, 1.09% Asian, 0.04% Pacific Islander, 0.28% from other races, and 1.03% from two or more races. Hispanic or Latino of any race were 0.87% of the population.
As of the 2000 census, the median income for a household in the MSA was $43,195, and the median income for a family was $51,873. Males had a median income of $35,402 versus $26,213 for females. The per capita income for the MSA was $21,851.
The Portland– Lewiston–South Portland Combined Statistical Area is made up of four counties in Maine. The statistical area includes two metropolitan statistical areas.  As of the 2000 Census, the CSA had a population of 591,361 (a July 1, 2009 estimate placed the population at 623,365). 
Metropolitan atatistical areas:
- Portland-South Portland-Biddeford (Cumberland, Sagadahoc, and York counties)
- Lewiston- Auburn ( Androscoggin County)
An alternative federal government delineation of Portland's metropolitan area is the Portland–South Portland, ME Metropolitan New England City and Town Area. A New England City and Town Area (NECTA) is typically a finer-grained definition of a metropolitan area because it is based on cities and towns rather than entire counties. The Portland–South Portland NECTA consists of 24 cities and towns in Cumberland County, 14 cities and towns in York County, and the town of Durham in Androscoggin County. 
Other parts of the Southern Maine region are identified as components of other NECTAs. The towns of Sanford and Shapleigh in York County form the Sanford, Maine, Micropolitan NECTA. The Brunswick, Maine, Micropolitan NECTA consists of two towns in Cumberland County, one city and eight towns in Sagadahoc County, and three towns in Lincoln County. Two metropolitan NECTAs centered in New Hampshire, the Dover-Durham, NH-ME Metropolitan NECTA (anchored by the principal cities of Dover and Durham, New Hampshire) and the Portsmouth, NH-ME Metropolitan NECTA (anchored by Portsmouth, New Hampshire) each include three York County towns. The Lewiston-Auburn Metropolitan NECTA is defined as including 11 Androscoggin County cities and towns, as well as four towns in Oxford County and one in Kennebec County. 
Similar to a CSA, the Portland–Lewiston–South Portland Combined NECTA is defined to consist of the Portland–South Portland and Lewiston–Auburn Metropolitan NECTAs and the Brunswick and Sanford Micropolitan NECTAs. The three York County towns that are included in the Portsmouth, New Hampshire Metropolitan NECTA are, however, considered to be part of the Boston–Worcester–Providence, MA–RI–NH–CT–ME Combined NECTA. 
The state of Maine uses NECTAs as one basis for defining labor market areas for purposes of compiling and reporting statistics on employment and unemployment. Labor market area definitions used for the Portland area include the Portland–South Portland–Biddeford Metropolitan Area, the Sanford Micropolitan Area, and the combination of these two areas, known as Portland–South Portland–Sanford combined statistical area. 
- "CPH-T-5. Population Change for Metropolitan and Micropolitan Statistical Areas in the United States and Puerto Rico (February 2013 Delineations): 2000 to 2010" (PDF). United States Census Bureau. Retrieved April 3, 2013.
- "OMB Bulletin No. 13-01: Revised Delineations of Metropolitan Statistical Areas, Micropolitan Statistical Areas, and Combined Statistical Areas, and Guidance on Uses of the Delineations of These Areas" (PDF). United States Office of Management and Budget. February 28, 2013. Retrieved April 3, 2013.
- "American FactFinder". United States Census Bureau. Retrieved 2008-01-31.
- "Table 2. Annual Estimates of the Population of Combined Statistical Areas: April 1, 2000 to July 1, 2009 (CBSA-EST2009-02)". 2009 Population Estimates. United States Census Bureau, Population Division. 2010-03-23. Archived from the original ( CSV) on April 20, 2010. Retrieved 2010-03-26.
- "Labor Market Area Definitions". State of Maine Center for Workforce Research and Information. Retrieved April 3, 2013.