Is Merrimack County, NH's population growing or shrinking?
Refreshed annually
It grew by 531 between 2024 and 2025. Changes in population can reflect birth and death rates, immigration patterns, regional shifts, and even the overall health of the economy. The 0.34% annual increase was primarily driven by people moving from other states.
In the decade between 2015 and 2025, Merrimack County, NH’s population grew by 6.3%.
+531
population change (2024 to 2025)
+0.34%
percent change in population (2024 to 2025)
Since 2000, Merrimack County, NH’s population increased 23 out of 25 years. The largest increase occurred between 2001 and 2002, when Merrimack County, NH gained 2,800 residents. Its largest decline occurred between 2009 and 2010 when there were 2,400 fewer residents.
Merrimack County, NH gained 531 residents between 2024 and 2025.
Annual population change, 2001–2025
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What contributes to population change in Merrimack County, NH?
A county’s population is influenced by three factors:
- Natural population change: If births outnumber deaths in a given year, natural population growth is positive. If deaths exceed births, it is negative. Between 2024 and 2025 natural population change was negative in Merrimack County, NH, with deaths exceeding births by 411.
- Immigration: international migration directly into or out of a county: If more people move in than move out, population change from immigration is positive. If more people move out than move in, it’s negative. Between 2024 to 2025, Merrimack County, NH’s population change from immigration was positive with about 130 more people coming from another country directly to Merrimack County, NH than leaving.
- Domestic migration, moving between counties: Between 2024 to 2025, Merrimack County, NH’s population change from domestic migration was positive with about 810 more people coming from any other county in the US.
Between 2024 and 2025, domestic migration was the primary driver of population growth in Merrimack County, NH.
Components of population change from previous year, 2011–2025
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Methodology
USAFacts standardizes data, in areas such as time and demographics, to make it easier to understand and compare.
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USAFacts endeavors to share the most up-to-date information available. We sourced the data on this page directly from government agencies; however, the intervals at which agencies publish updated data vary.
