How you go about researching the history of your house will depend on where you live. In most places, start with the local historical society or library. The National Archives also can be a good resource, as can state archives. One thing to keep in mind as you're doing research is that some records, especially older ones, can contain incorrect information. People have been known to lie to census-takers, for example, and even something as straightforward as the date a house was built might be incorrectly recorded in some archive, so try to confirm information with more than one source.

Historical data are more readily available in some areas than others. The following list of resources is not exhaustive, but it should give you a good start.

DISTRICT

The Historical Society of Washington, D.C. (www.citymuseumdc.org) has put together a research guide (www.dclibrary.org/ washingtoniana/gd-buildings- pth.pdf) in cooperation with the Washingtoniana Division of the D.C. Public Library. The Washingtoniana Division, on the third floor of the Martin Luther King Jr. Memorial Library at 901 G. St. NW, has maps, building permits, city directories and census records. The Historical Society, located at 801 K St. NW, has photographs and books helpful in research, including a collection of 4,000 photographs from the late 1940s and early 1950s by John P. Wymer, a statistician who attempted to take pictures of every neighborhood -- almost every block -- in the city.

Some building permits and other records are also at the National Archives, at 700 Pennsylvania Ave. NW. Property owner and sales records are at the Recorder of Deeds, at 515 D St. NW.

Tax assessments can be searched on the D.C. government Web site (cfo.dc.gov/otr/cwp/view,a,1330,q, 594345.asp).

The Peabody Room at the Georgetown Neighborhood Library (dclibrary.org/branches/geo/peabody.html), at Wisconsin Avenue and R Street NW, has Georgetown-specific maps and other records.

The Web site H-DC: Washington, D.C., History and Life (www.h-net.org/{tilde}dclist) has lots of links to resources, maps and information about neighborhoods.

ALEXANDRIA

The Alexandria Library's Web site has a guide specifically for people researching their houses' history (www.alexandria.lib.va.us/lhsc_online_collection_guides/house/house.html). The Web site (www.alexandria.lib.va.us/branches/lhsc.html) also has the information from building and repair permits from 1896 to 1928, old photographs and property tax papers from Old Town. Most of the information can be found at the Kate Waller Barrett Branch at 717 Queen St. Wills, tax records and maps are on microfilm.

Deeds are on the third floor of the Alexandria Courthouse at 520 King St., and many are also at the Barrett Branch. Building permits for part of the 20th century are at the Alexandria Records and Archives Center at 801 S. Payne St.; the rest are at the Barrett branch of the library.

The Alexandria Lyceum Web site also has a guide to researching your house (oha.ci.alexandria.va.us/oha-main/oha-hist-house-sleuth ing.html).

The library's Web site points out that because of the way Alexandria came to be an independent city, some records might also be found in the District, Arlington County or Fairfax County.

ARLINGTON COUNTY

A guide to researching your house's history is available in the Virginia Room at Arlington's Central Library at 1015 N. Quincy St. (www.co.arlington.va.us/Departments/Libraries/history/ LibrariesHistoryLocalHistory. aspx). The room also has maps dating from the 1600s as well as census and court records. The maps are important because streets in Arlington were renamed around 1935.

Arlington has an online real estate assessment database (www.arlingtonva.us/Departments/RealEstate/RealEstateAssessments Main.aspx) with owner's name, sales history, a legal description of the property and other information.

Deeds, mortgages and wills are in Suite 6200 of the Arlington County Circuit Court at 1425 N. Courthouse Rd.

As with Alexandria, some records may be in other jurisdictions, including the District.

FAIRFAX COUNTY

The main resources available in Fairfax are at the library's Virginia Room (www.co.fairfax.va.us/library/branches/vr/default.htm), at 3915 Chain Bridge Rd., and at the county courthouse at 4110 Chain Bridge Rd.

The Virginia Room has maps, old newspapers, some deed and tax records, as well as books on the history of the area. Census data is available on microfilm in the Virginia Room, as well as online. The courthouse has other deed records, as well as wills and a subject index for houses that have names. To research, start out at the office of land records on the third floor.

Real estate assessments are online (icare.fairfaxcounty.gov/Main/Home.aspx).

Most records are done on a county basis, but individual cities may also have information. For example, the Fairfax City Hall at 10455 Armstrong St. has some records, and the Historic Fairfax City at 10209 Main St. has books on genealogy of the city's founders and the history of the town. The Great Falls Historical Society has books about houses and the surrounding area, and its Web site (gfhs.org) has a Local Lore section.

Fairfax County was created from Prince William County, and some areas that used to be in the county are now in Loudoun County or Arlington, so some records may be in other jurisdictions.

PRINCE WILLIAM COUNTY

The Ruth E. Lloyd Information Center, known as RELIC (www.co.prince-william.va.us/default.aspx?topic=040034001060 001235), at the Bull Run Regional Library, 8051 Ashton Ave. in Manassas, has information on local history including maps, county records, census records and city directories. The RELIC newsletter, available through the library, had a two-part series in May dealing more in depth with researching a home. Deeds are available at the county circuit court, at 9311 Lee Ave. in Manassas. Property assessment information can be found at www4.pwcgov.org/ realestate/LandRover.asp.

LOUDOUN COUNTY

The Thomas Balch Library, at 208 W. Market St. in Leesburg, has information on county history, including maps, photographs, newspapers, property tax records and census records. Also, the Virginia Department of Historic Resources (www. dhr.virginia.gov) can be a good source of information, with a survey of older homes. The county courthouse, at 18 E. Market St. in Leesburg, also has records.

MONTGOMERY COUNTY

The Montgomery County Historical Society (www.montgomeryhistory.org), at 103 W. Montgomery Ave., has a handout that tells people how to get started and use public records in their search. It also has maps, wills, street plans and photographs as well as general information on areas of the county and towns. The society also has census data on microfilm, as does the Rockville Regional Library, at 99 Maryland Ave.

The Montgomery County Historical Society also is in charge of the county archives. Those are at the Red Brick Courthouse, at 29 Courthouse Square in Rockville, as are the records of the county government since 1948. Also at the courthouse are Rockville records, including photos, some land and property records, and oral histories.

Property records, including deeds and mortgages, are at the Judicial Center at 50 Maryland Ave. in Rockville. A property data search can also be done through the Maryland Department of Assessments and Taxation (sdatcert3.resiusa.org/rp_rewrite).

The Montgomery County Department of Permitting Services (permittingservices.montgomery countymd.gov) has information on building permits.

PRINCE GEORGE'S COUNTY

The Maryland Room at the Hyattsville Library (www.pgcmls. info/SpColl/Maryland/Maryland Room.html), at 6530 Adelphi Rd., has census data, wills, city directories and land records. Much of the information, however, exists for only the area around Hyattsville, including directories. It had copies of Sanborn Fire Insurance maps for the area, but they were stolen and have yet to be replaced, librarian John Krivak said. There are also maps that were filed with the county each time a subdivision was started, but they don't show which houses were built when.

A title search can be done at the county courthouse, at 14735 Main St. in Upper Marlboro, and the Maryland Room has a title search handbook.

Krivak also said that title insurance is mandatory in Maryland, so homeowners can contact the firm that did the title search on their house to get the information.

HOWARD COUNTY

The Howard County Historical Society (www.hchsmd.org), at 8324 Court Ave. in Ellicott City, has books on local history as well as marriage licenses, deeds, maps and aerial photos. It also has census records on microfilm. Most of the society's records are at least 50 to 70 years old, said Mike Walczak, director of the society. The Department of Planning and Zoning, at 3430 Court House Dr. in Ellicott City, has the historic site survey, and the State Archives in Annapolis are another good resource.

Sources: Washington Post research, Alexandria Lyceum historian Michael Miller, Shannon Davis of the Arlington Heritage Alliance, Judy Knudsen of the Arlington County Virginia Room, Matthew Gilmore of H-DC, Suzanne Levy of the Fairfax County Library Virginia Room, Fairfax historian Ed Trexler, area historian Milburn Sanders, Prince William historian Donald Wilson, Childs Burden of the Loudoun County Historical Society, Karen Lottes of the Montgomery County Historical Society, Terry Lachin of Peerless Rockville, John Krivak at the Prince George's Maryland Room, and Mike Walczak of the Howard County Historical Society.