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New Mexico County
Los Alamos County, New Mexico
Los Alamos - where the atomic bomb was built - from the Manhattan Project's Los Alamos Laboratory (J. Robert Oppenheimer led the secret city of scientists on the Pajarito Plateau from 1943 to 1945 - the most extraordinary concentration of scientific genius in history assembled on a remote New Mexico mesa to design and build the world's first nuclear weapons - Los Alamos National Laboratory remains one of the most important scientific research institutions in the world, and the Bradbury Science Museum documents the Manhattan Project and the laboratory's continuing work) and the Bandelier National Monument's ancestral Pueblo cliff dwellings on the plateau's volcanic landscape.
Affiliate disclosure: This page contains affiliate links. We may earn a commission if you use them, at no extra cost to you. Our editorial recommendations are independent of these relationships.
What do you need to do?
Tell us your goal and we'll guide you step-by-step to the right office, forms, and official resources.
Office: Los Alamos County Office of Emergency Management – confirm current contact via losalamosnm.gov. A new dedicated Emergency Operations Center (EOC) is under construction to replace ad hoc use of fire/police training rooms.
Police: Los Alamos County Police Department – 2500 Trinity Drive, Los Alamos, NM 87544; confirm current non-emergency phone via losalamospd.com. Genuinely reported to have the lowest crime rate in New Mexico.
Notes: For an active emergency, call 911.
Roads & Utilities
ROADS & TRANSPORTATION
Roads: NM-4 and NM-502 serve Los Alamos, perched at roughly 7,300 feet on the Pajarito Plateau in northern New Mexico.
Notes: Los Alamos County is genuinely New Mexico’s smallest county by area (109 square miles) and is an “incorporated county” – a unique combined city-county government established under a special provision of the state constitution, giving it both municipal and county authority. NAMING TRAP: do not confuse with the unrelated unincorporated community of Los Alamos, California (Santa Barbara County).
Business & Permits
BUILDING & PERMITS
Office: Los Alamos County – confirm current contact via losalamosnm.gov.
Notes: Los Alamos is genuinely, world-famously the birthplace of the Manhattan Project – the secret WWII effort that built the world’s first atomic bomb, beginning in 1943. This history is preserved today at the Manhattan Project National Historical Park (NPS, Los Alamos unit contact: (505) 661-6277). Los Alamos National Laboratory remains the county’s largest employer. The county is also the gateway to Bandelier National Monument and the Valles Caldera National Preserve.
Veterans Services
VETERANS SERVICES
Office: Los Alamos County Veterans Service – confirm current contact via losalamosnm.gov.
Federal: Albuquerque VA Medical Center (long distance).
Libraries
LIBRARIES
Los Alamos County Library System – Mesa Public Library, 2400 Central Avenue, Los Alamos, NM 87544; genuinely founded in 1943 as a subscription library funded by a $5 donation from 70 local families, made free to all in 1945; over 160,000 items including a Southwest Collection of 3,400+ books; current building (1994) designed by architect Antoine Predock. White Rock Branch Library, 10 Sherwood Boulevard, White Rock, NM.
Parks & Recreation
PARKS & RECREATION
Key Assets: Manhattan Project National Historical Park, Bandelier National Monument, Valles Caldera National Preserve, Pajarito Ski Resort, and over 150 miles of hiking/biking/equestrian trails are the county’s premier attractions.
Notes: The genuine Manhattan Project/atomic bomb history is one of the most significant local facts covered anywhere in this project.
GIS & Maps
GIS & MAPS
Appraisal/Parcel Search: Los Alamos County Assessor – confirm current contact via losalamosnm.gov.
Animal Services
ANIMAL SERVICES
Los Alamos County Animal Shelter/Animal Control (operated by the Police Department) – (505) 662-8222 | Toll-free/TTY (877) 261-4090; serves the incorporated county including White Rock. Cat adoptions include spay/neuter, vaccinations, and microchip; dog and cat adoption fees vary by age.
Environmental & Waste
ENVIRONMENTAL / WASTE MANAGEMENT
Office: Los Alamos County – confirm current contact via losalamosnm.gov.
NOTES: Los Alamos County is the second county in the New Mexico v3 A+ sourced redo’s third batch (Lincoln, Los Alamos, Luna, McKinley, Mora, Otero, Quay). The genuine Manhattan Project/atomic bomb history is one of the most significant local facts covered anywhere in this project. Naming trap: do not confuse with the unrelated town of Los Alamos, California. All contact information above was sourced via web search as of early August 2026 and should be reconfirmed directly with the relevant office before a visit, deadline-sensitive filing, or emergency-adjacent decision.
About Los Alamos County
Los Alamos County is where the atomic bomb was built – Oppenheimer’s secret city of Nobel laureates and brilliant scientists on the Pajarito Plateau designed humanity’s most consequential weapon in 1943-1945, and Los Alamos National Laboratory’s continuing work makes it one of the world’s most important scientific institutions.
Los Alamos (the county seat, population ~13,000) is one of the most educated communities in the United States – the concentration of PhD scientists at LANL gives Los Alamos the highest per-capita income in New Mexico and one of the highest educational attainment rates in the country.
All Services
Browse every category and topic available for this county.
Los Alamos County Assessor at 1000 Central Avenue, Suite 240, Los Alamos, NM 87544, phone 505-662-8025. NM assessed at one-third of market value.
Courts & Legal
Los Alamos County District Court at 2500 Trinity Drive, Suite C, Los Alamos, NM 87544, phone 505-662-9027, handles probate.
Marriage & Vital Records
Marriage licenses, divorce records, and birth & death certificates are handled by the following office(s):
COUNTY CLERK
1000 Central Ave., Los Alamos, NM 87544
(505) 662-8010
COUNTY CLERK — ELECTIONS
1000 Central Ave., Los Alamos, NM 87544
(505) 662-8010
Genealogy
PRIMARY STATEWIDE RESEARCH CENTERS (same across all New Mexico counties)
New Mexico State Records Center and Archives, 1205 Camino Carlos Rey, Santa Fe, NM 87507.
New Mexico Genealogical Society, P.O. Box 8283, Albuquerque, NM 87198.
County-level record sources
Los Alamos County Probate Court, Los Alamos (probate case files – see Probate section above).
Local societies
No dedicated Los Alamos County genealogical society was confirmed in available directories.
Probate & Estate
Losing someone and having to deal with courts and paperwork at the same time is hard. This section won’t make that easier, but it should tell you what to expect, what it costs, and where to go – so at least you’re not walking in blind.
Where to go
Los Alamos County Probate Court 2300 Trinity Drive (mail: P.O. Box 30), Los Alamos, NM 87544 (505) 662-8025
Los Alamos County is in north-central New Mexico, home to Los Alamos National Laboratory, seated in Los Alamos.
Step 1: figure out which path applies
New Mexico adopted the Uniform Probate Code. New Mexico has a dual court system: the county PROBATE COURT handles informal, uncontested probate matters with minimal court involvement, and has concurrent jurisdiction with the DISTRICT COURT over informal proceedings. The District Court alone handles formal probate – contested cases, determinations of heirship, and trust matters.
Small Estate Affidavit / Affidavit of Successor in Interest (N.M. Stat. § 45-3-1201) – available when the value of the entire estate (after liens and encumbrances) does not exceed $50,000 and does NOT include any real property. At least 30 days must have passed since death. This skips probate court entirely – the affidavit is presented directly to banks, the DMV, or other institutions holding the property.
Homestead Transfer Affidavit for Surviving Spouse (N.M. Stat. § 45-3-1205) – available 6 months after death, when the surviving spouse and decedent owned a homestead as community property valued at $500,000 or less (for property tax purposes). The affidavit is recorded with the county clerk and can avoid formal probate for the residence, but only if funeral expenses, expenses of last illness, and all unsecured debts have already been paid.
Informal Probate – the most common path for uncontested estates, filed with either the Probate Court or the District Court in the county where the decedent was domiciled. No hearing required.
Formal Probate – required for contested cases, disputes over heirship, or trust matters. Only the District Court can hear these.
Step 2: filing for informal or formal probate
File a petition with the Probate Court or District Court in the county where the decedent was domiciled. A probate may be started up to 3 years after death.
The court appoints the personal representative and issues Letters Testamentary or Letters of Administration.
The personal representative notifies creditors; New Mexico’s creditor claim period is 2 months from notice to creditors – one of the shortest in the country.
The personal representative inventories the estate’s assets, pays debts and expenses, and distributes the remaining assets according to the will or New Mexico’s intestacy statute.
The estate is closed, typically within 6 to 12 months for straightforward, uncontested cases.
What it costs
The filing fee for probate in Probate Court is generally around $30 – notably lower than in most states. District Court filing fees run higher, commonly $100–$232 depending on the county and complexity.
New Mexico does not set a fixed statutory percentage for personal representative compensation; courts typically look to a reasonable guideline of about 2–4% of the estate’s value.
New Mexico has no state estate tax and no state inheritance tax. Only the federal estate tax could apply, and only to very large estates.
Probate filings, estate administration, and guardianship matters are handled by the following office(s):
Public Safety & Arrests
Arrest records, inmate search, and law enforcement services are handled by the following office(s):
SHERIFF
1000 Central Ave., Los Alamos, NM 87544
(505) 662-8222
Elections & Voting
Voter registration, polling locations, and elections information are handled by the following office(s):
COUNTY CLERK — ELECTIONS
1000 Central Ave., Los Alamos, NM 87544
(505) 662-8010
ELECTIONS
1000 Central Ave., Los Alamos, NM 87544
(505) 662-8010
Health & Human Services
Offices & Contacts
Health services, social services, and assistance programs are handled by the following office(s):
NM HSD — Los Alamos
(505) 662-8100
Los Alamos Medical Center
losalamosmeds.com (Los Alamos — quality community hospital)
Public Health Information
PUBLIC HEALTH
Office: Los Alamos County Health and Public Safety – confirm current contact via losalamosnm.gov.
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Last verified June 2026
County Facts
County Seat: Los Alamos
Population: 19,000
Area: 109 sq mi (NM's smallest county by area)
Established: 1949
Tier: 3
Public Records
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Search public records for Los Alamos County residents.
