# Maine statistical areas

The U.S. State of Maine currently has five statistical areas that have been delineated by the Office of Management and Budget (OMB). On July 21, 2023, the OMB delineated one combined statistical area, three metropolitan statistical areas, and one micropolitan statistical area in Maine. As of 2023, the largest of these is the Portland-Lewiston-South Portland, ME CSA, comprising the region around Maine's largest city of Portland.

## Background

The Office of Management and Budget (OMB) has designated more than 1,000 statistical areas for the United States and Puerto Rico. These statistical areas are important geographic delineations of population clusters used by the OMB, the United States Census Bureau, planning organizations, and federal, state, and local government entities.
The OMB defines a core-based statistical area (commonly referred to as a CBSA) as the county or counties (or county-equivalents) surrounding at least one densely-settled core of at least 10,000 population, "plus adjacent counties having a high degree of social and economic integration with the core as measured through commuting ties with the counties containing the core". The OMB further divides core-based statistical areas based on population into metropolitan statistical areas (MSAs) for those with at least 50,000 and micropolitan statistical areas (μSAs) for those with 10,000 to 49,999 people.
The OMB defines a combined statistical area (CSA) as two or more adjacent core-based statistical areas where the employment interchange rate (% commuting from A to B plus % commuting from B to A) is at least 15%. The primary statistical areas (PSAs) include all combined statistical areas and any core-based statistical area that is not a constituent of a combined statistical area.

## Table

The five United States statistical areas and 16 counties of the State of Maine :
| Combined statistical area | 2023 population (est.) | Core-based statistical area | 2023 population (est.) | County | 2023 population (est.) |
| Portland-Lewiston-South Portland, ME CSA | 680,094 | Portland-South Portland, ME MSA | 566,329 | Cumberland County, Maine | 310,230 |
| Portland-Lewiston-South Portland, ME CSA | 680,094 | Portland-South Portland, ME MSA | 566,329 | York County, Maine | 218,586 |
| Portland-Lewiston-South Portland, ME CSA | 680,094 | Portland-South Portland, ME MSA | 566,329 | Sagadahoc County, Maine | 37,513 |
| Portland-Lewiston-South Portland, ME CSA | 680,094 | Lewiston-Auburn, ME MSA | 113,765 | Androscoggin County, Maine | 113,765 |
| none | none | Bangor, ME MSA | 155,312 | Penobscot County, Maine | 155,312 |
| none | none | Augusta-Waterville, ME μSA | 127,259 | Kennebec County, Maine | 127,259 |
| none | none | none | none | Aroostook County, Maine | 67,351 |
| none | none | none | none | Oxford County, Maine | 59,905 |
| none | none | none | none | Hancock County, Maine | 56,526 |
| none | none | none | none | Somerset County, Maine | 51,302 |
| none | none | none | none | Knox County, Maine | 40,977 |
| none | none | none | none | Waldo County, Maine | 40,620 |
| none | none | none | none | Lincoln County, Maine | 36,507 |
| none | none | none | none | Washington County, Maine | 31,555 |
| none | none | none | none | Franklin County, Maine | 30,828 |
| none | none | none | none | Piscataquis County, Maine | 17,486 |
| State of Maine | State of Maine | State of Maine | State of Maine | State of Maine | 1,395,722 |

## Core-based statistical areas

The following table provides the in-state population ranking of each CBSA along with its rate of population change over time.
The four core-based statistical areas of the State of Maine :
| 2023 rank | Core-based statistical area | Population | Population | Population | Population | Population |
| 2023 rank | Core-based statistical area | 2023 estimate | Change | 2020 Census | Change | 2010 Census |
| 1 | Portland-South Portland, ME MSA | 566,329 | +2.64% | 551,740 | +7.32% | 514,098 |
| 2 | Lewiston-Auburn, ME MSA | 113,765 | +2.36% | 111,139 | +3.19% | 107,702 |
| 3 | Bangor, ME MSA | 155,312 | +2.05% | 152,199 | −1.12% | 153,923 |
| 4 | Augusta-Waterville, ME μSA | 127,259 | +2.93% | 123,642 | +1.22% | 122,151 |

## Combined statistical areas

The following table provides the in-state population ranking of each CSA along with its rate of population change over time.
The one combined statistical area of the State of Maine :
| 2023 rank | Combined statistical area | Population | Population | Population | Population | Population |
| 2023 rank | Combined statistical area | 2023 estimate | Change | 2020 Census | Change | 2010 Census |
| 1 | Portland-Lewiston-South Portland, ME CSA | 680,094 | +2.60% | 662,879 | +6.61% | 621,800 |