County · code 34025
Monmouth CountyNew Jersey
Monmouth County is in New Jersey and was created in 1683 as one of four original counties in East New Jersey, with its county seat at Freehold. The county is named after Monmouthshire.
- Founded1683
- County seatFreehold
- Named forMonmouthshire, Wales
- Land area468 sq mi + 193 sq mi water
- Population643,615 2020 Census
- Parcels mapped264,376 checked 15 October 2026
Where it is
Monmouth on the map of New Jersey
New Jersey has 21 counties and county equivalents, each with its own records office. Shapes with a page are links.
History
Founded in 1683
An old deed may name a county that no longer exists, or a boundary that has since moved.
On 7 March 1682/1683, Monmouth County was created as one of four original counties in East New Jersey. In 1687, after the proprietors of East and West New Jersey agreed on a new division between their colonies, Monmouth County gained territory from Burlington Court in southern West New Jersey, with the boundary becoming known as the Keith Line. When the proprietors surrendered their governing rights to Queen Anne in 1702, East and West New Jersey united into the single royal province of New Jersey, and Monmouth County became a county in the royal province with unchanged boundaries. Over subsequent centuries, Monmouth County exchanged and adjusted boundaries with neighboring Middlesex County multiple times, and gained and lost territory with Ocean County following its creation in 1850.
- 1683Monmouth County created 7 March 1682/1683. Monmouth was created as one of four original counties in East New Jersey; Non-County Area (East) eliminated. · Shaw, 1:212, 231; Snyder, 10-11, 29-31; Wall and Pickersgill, 1:63
- 1687Gained territory 8 January 1686/1687. Monmouth gained from Burlington Court in Indefinite Counties Area in southern West New Jersey when commissioners from East and West New Jersey agreed on a new division between their colonies. The line ran west of the boundary specified in the Quintipartite Deed of 1676. The southern part of this line was demarcated in the spring of 1687 and became known as the Keith Line, named for the surveyor. · Snyder, 9, 31
- 1702Became part of New Jersey Proprietors of East and West New Jersey surrendered to Queen Anne their rights to govern their colonies, and the two colonies were united into the single royal province of New Jersey. Monmouth became a county in the royal province of New Jersey; boundaries were unchanged. · Pomfret, Colonial New Jersey, 87; Snyder, 13; Swindler, 6:439-445, Van Zandt, 79
- 1710Exchanged territory 21 January 1709/1710. Monmouth exchanged with Middlesex. · Paterson, 2-3; Snyder, 30-32
- 1844Gained territory Monmouth gained from Middlesex. · N.J. Acts 1844, p. 141; Snyder, 38
Show all 16 changes
- 1683Monmouth County created 7 March 1682/1683. Monmouth was created as one of four original counties in East New Jersey; Non-County Area (East) eliminated. · Shaw, 1:212, 231; Snyder, 10-11, 29-31; Wall and Pickersgill, 1:63
- 1687Gained territory 8 January 1686/1687. Monmouth gained from Burlington Court in Indefinite Counties Area in southern West New Jersey when commissioners from East and West New Jersey agreed on a new division between their colonies. The line ran west of the boundary specified in the Quintipartite Deed of 1676. The southern part of this line was demarcated in the spring of 1687 and became known as the Keith Line, named for the surveyor. · Snyder, 9, 31
- 1702Became part of New Jersey Proprietors of East and West New Jersey surrendered to Queen Anne their rights to govern their colonies, and the two colonies were united into the single royal province of New Jersey. Monmouth became a county in the royal province of New Jersey; boundaries were unchanged. · Pomfret, Colonial New Jersey, 87; Snyder, 13; Swindler, 6:439-445, Van Zandt, 79
- 1710Exchanged territory 21 January 1709/1710. Monmouth exchanged with Middlesex. · Paterson, 2-3; Snyder, 30-32
- 1822Boundary clarified Water boundaries of Monmouth, Essex, and Middlesex were redefined to assert New Jersey's claim to the western half of Arthur Kill, the water separating Staten Island, N.Y., from the New Jersey mainland. · N.J. Acts 1822, p. 35; Snyder, 34-36
- 1844Gained territory Monmouth gained from Middlesex. · N.J. Acts 1844, p. 141; Snyder, 38
- 1845
- 1847
- 1850
- 1851Boundary clarified Boundary between Monmouth and Ocean clarified (no change).with Oceanno change· N.J. Acts 1851, p. 323
- 1866Boundary clarified Monmouth's northern boundary in Raritan Bay redefined.no change· N.J. Acts 1866, p. 964; Snyder, 42
- 1869
- 1892Boundary clarified Water boundries of Monmouth, Bergen, Hudson, Middlesex, and Union redefined to match the New Jersey-New York interstate boundary agreement of 1834, as detailed by joint commissions in 1887 and 1889. · N.J. Acts 1892, p. 441; Snyder, 44-45
- 1906Boundary clarified Coastal limits of Monmouth, Atlantic, Cape May, and Ocean redefined. · N.J. Acts 1906, p. 542; Snyder, 45
- 1928
- 1939Gained territory Monmouth gained small area in Madison township from Middlesex. · N.J. Acts 1939, p. 657; Snyder, 47
Land and parcels
What the maps cover in Monmouth
Who publishes each layer, how good it is, and when we last checked.
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Parcels Good enough
Lot lines and tax-map numbers for 264,376 parcels. Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
checked 15 October 2026 -
Address points Official
One point per address, 244,551 in all from NJOGIS.
edited 23 September 2026 · checked 14 October 2026 -
Buildings Reference
Roof outlines traced from aerial imagery from FEMA Response Geospatial Office with Oak Ridge National Laboratory (ORNL). Good for seeing what is on a lot; not accurate enough to set a fence from.
checked 18 October 2026
- Official
- from the office that keeps the record
- Good enough
- a reliable statewide or national copy
- Fallback
- a guide only; check the official record
- Missing
- nothing public found yet
People and land
Monmouth by the Census
Source: US Census Bureau, 2020 Census; US Census Bureau, 2020 Gazetteer Files. Not endorsed or certified by the Census Bureau.
Rules and offices
Who to ask before you build, dig or sell
Official county pages only. We link to them; we do not copy them, because they change.
Inside a city or town, permits usually come from that city rather than the county.
County government
- County government
The official website of Monmouth County.
See your own lot on these maps
Open Monmouth County on Parcel Chart's free map and click your parcel. Save it with a free account; the full record of your place (site map, projects, documents) is Pro, in early access.
Questions
Common questions about Monmouth County
- When was Monmouth County founded?
- Monmouth County was founded in 1683, and named after Monmouthshire, Wales.
- What is the county seat of Monmouth County?
- The county seat of Monmouth County is Freehold.
- Is there an online parcel map for Monmouth County?
- Yes. A public source publishes a parcel map of 264,376 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
- Has Monmouth County's boundary or name changed?
- Monmouth County was created in 1683. Since then the Atlas of Historical County Boundaries records 10 later changes, chiefly involving Middlesex County and Ocean County.
- Is my lot in a flood zone?
- We do not have flood maps for Monmouth County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.
Nearby