Data Sources and Methodology

Primary sources, not secondary summaries

Most historical research tools work by searching the web or aggregating secondary sources. Aubrey is different. Every data point in an Aubrey report traces back to a primary federal record: a National Register nomination document, a battlefield survey, a General Land Office patent, a USGS geological survey, a census enumeration.

This means the data is authoritative, citable, and consistent. When Aubrey identifies a Civil War engagement near your location, it is drawing on the same CWSAC survey that professional historians cite. When it describes your area's geology, it is drawing on USGS data.

The nine data sources below constitute the full corpus that Aubrey searches for every US report. Where data is available for a location, Aubrey synthesises it into a structured section with sources cited. Where data is absent, the report states this explicitly. For narrative descriptions not covered by federal records, Aubrey supplements with Wikipedia content adapted under the CC BY-SA 4.0 licence, attributed on each relevant page.

The NRHP is the official federal list of districts, sites, buildings, structures, and objects deemed worthy of preservation for their historical, architectural, or cultural significance. Each listing includes a nomination document detailing the property's history, period of significance, physical description, and statement of significance. Aubrey searches all NRHP listings within a configurable radius of any US location, extracting period of significance, resource type, and architectural details.

Aubrey's battlefield database combines records from the CWSAC's definitive survey of 384 principal Civil War battle sites with the ABPP's broader survey of over 1,500 engagements across all American conflicts. Each record includes location coordinates, opposing forces, date, outcome, and significance assessment. Aubrey cross-references engagement records against report coordinates to surface all relevant military history within a searchable radius.

The GLO cadastral survey system established the Public Land Survey System (PLSS), which divided most US land west of the original 13 colonies into townships, ranges, and sections. GLO records include original survey plats, field notes, and land patents documenting every parcel of federal land transferred to private ownership. These records are the foundation of American land title history and are essential for tracing any property's ownership chain back to its original federal patent.

The USGS has systematically surveyed the geology and topography of the United States since 1879. Aubrey draws on USGS geological and topographic data to describe the underlying bedrock, rock formations, soil types, and landscape features at any US location. The geological context of a site often explains its historical use — river terraces favoured early settlement, limestone country shaped agricultural patterns, mineral deposits drove frontier expansion.

The US Census has recorded population data at county level since 1790. Aubrey draws on county-level census data to contextualise a location within its broader demographic history — growth patterns, population changes, and the expansion of settlement. Agricultural schedules (1850–1880) document farm values, crop production, and livestock counts at county level, providing essential context for understanding the rural economy of any US location in the nineteenth century.

Aubrey's Indigenous heritage data is compiled from federal treaty records, BIA tribal documentation, NPS archaeological assessments, and academic ethnographic sources. Each entry covers traditional territory boundaries, documented presence dates, language family, federal recognition status, and primary source citations. Treaty records — 374 ratified as of the nineteenth century — are cross-referenced to identify which nation held territory at a given location before US settlement.

Aubrey's biographical database covers historical figures connected to specific US locations, from colonial founders and Revolutionary War officers to Civil War commanders, frontier leaders, and notable community members. Each record includes birth and death dates, locations of significance, primary occupations, and source citations. The database is drawn from the Biographical Directory of the United States Congress, state legislative records, military rosters, and digitised historical sources.

Aubrey's historical events database records significant events by location, including founding dates, battles, migrations, natural disasters, industrial milestones, and community turning points. Every entry carries a source citation. The database is cross-referenced against report coordinates to surface events relevant to the searched location.

For certain content types — including state history narratives, biographical summaries, indigenous group descriptions, colonial events, battlefield significance text, and archaeological site entries — Aubrey incorporates text adapted from Wikipedia. Wikipedia content is used only where primary federal records do not include narrative descriptions. All adapted text is clearly attributed on the relevant page.