How to find the history of your house: the six free records (US)
Most of a house's story sits in six kinds of public record, and most of them are free online. This is the order we work in for a House History Report; it is also the order to work in yourself.
1. The deed index (who owned it)
The county recorder (sometimes "register of deeds" or "clerk") keeps an index of every deed by name and, in many counties, by parcel. Many counties have the index online, some with the deed images; the assessor's parcel page often shows a short ownership history too. Start from your own deed: the sellers' names and the lot or parcel number take you back one owner at a time. What is usually missing: deeds before the index was computerised (often before the 1970s or 1980s) are on microfilm at the courthouse, so the online chain can stop short.
2. The census (who lived there, 1850–1950)
The federal census lists everyone in the house every ten years from 1850 (names of all household members) to 1950, the latest released. Each sheet from 1880 on carries the street and house number in the margin, so you can search an address rather than a name. The 1890 census was lost to fire. Images are free with a FamilySearch account; the 1950 census is free on the National Archives site. What is usually missing: house numbers changed and streets were renamed, so a 1920 address may not be today's number.
3. City directories (every year in between)
Before phone books, city directories listed every adult by name with occupation and address, and from the early 1900s many have a street section too. Public libraries and the Internet Archive have scanned runs for most cities; a directory a year either side of a census fills the gaps and shows when a family arrived or left.
4. Fire-insurance maps (what stood on the lot)
Sanborn fire-insurance maps drew every building in a town, colour-coded by material, with porches, outbuildings and storeys, in editions a few years apart from the 1880s to the 1950s. The Library of Congress has thousands of them free online. Two editions side by side show when a house appeared, when a porch was enclosed and when the garage went up.
5. Newspapers (what happened there)
Chronicling America (Library of Congress) is free and covers many local papers to 1963; many state libraries run their own free archives. Search the exact address in quotes and the owners' names: weddings "at the home of", building notices, sales, fires and the occasional photograph.
6. Permits and registers (the official paper)
Building permits exist in some cities from the 1880s, but few are online before the 1990s; the city archive or the planning counter has the paper. The National Register of Historic Places and state and local historic registers carry a full write-up when a house or its district is listed.
What a report cannot do
It cannot name the people who live in a house now, cannot fill a gap the records leave, and cannot promise a photograph. A good one says what was looked for and not found, and where the record may still be.
If you would rather have it done: House History Report reads all six for your address and writes it up as a PDF within 2 days, $79, from public records only. The invented sample is at /sample/. For the people rather than the house, see Family Tree Chart · Stuck on one ancestor? One question, answered from the records: Brick Wall Report.