| U.S., Social Security Applications and Claims Index, 1936-2007 | 133,418,498 |
| United States Patent and Trademark Office, U.S. Patents, 1970-2019 | 29,108,340 |
| U.S., IRS Tax Assessment Lists, 1862-1918 | 8,850,878 |
| U.S., Indexed County Land Ownership Maps, 1860-1918 | 6,940,589 |
| U.S., Patent and Trademark Office Patents, 1790-1909 | 3,577,054 |
| U.S., Freedmen's Bureau Records, 1865-1878 | 3,235,082 |
| U.S., Appointments of U. S. Postmasters, 1832-1971 | 1,514,110 |
| U.S., Letters Received by the Office of Indian Affairs, 1824-1881 | 907,100 |
| U.S., Freedman's Bank Records, 1865-1874 | 685,322 |
| Maine, U.S., York County, Probate Estate Files, 1690-1917 | 508,689 |
| U.S., Union Provost Marshal Files of Individual Civilians, 1861-1866 | 502,957 |
| U.S., Subject Index to Correspondence and Case Files of the Immigration and Naturalization Service, 1903-1959 | 410,831 |
| Maine, U.S., Wills and Probate Records, 1584-1999 | 370,420 |
| U.S., Final Accountability Rosters of Evacuees at Relocation Centers, 1942-1946 | 149,092 |
| U.S., Union Provost Marshal Files of Two or More Civilians, 1861-1866 | 107,471 |
| U.S., Revolutionary War Pension and Bounty-Land Warrant Application Files, 1800-1900 | 83,050 |
| U.S., Records Related to Enrollment of Eastern Cherokee by Guion Miller, 1908-1910 | 79,496 |
| U.S., War Bounty Land Warrants, 1789-1858 | 76,126 |
| Maine, U.S., Piscataquis County, Deed Books, 1838-1902 | 56,970 |
| Maine Court Records, 1696-1854 | 55,254 |
| U.S., House of Representative Private Claims, Vol. 1 | 22,958 |
| U.S., House of Representative Private Claims, Vol. 3 | 20,768 |
| Abraham Lincoln Papers | 20,158 |
| U.S., F.B.I. Deceased Criminal Identification Files, 1971-1994 | 19,807 |
| Mayflower Deeds and Probates, 1600-1850 | 18,601 |
| U.S., House of Representative Private Claims, Vol. 2 | 18,363 |
| U.S., Ratified Indian Treaties and Chiefs, 1722-1869 | 10,048 |
| U.S., Jewish Names in Selected State Department Files, 1910-1929 | 9,724 |
| U.S. and World Atlases, 1822-1923 | 8,170 |
| U.S., Definitive List of Slaves and Property, 1827-1828 | 4,931 |
| Ireland, Irish Emigration Lists, 1833-1839 | 3,421 |
| U.S., Department of the Interior Decisions on Pensions and Bounty-Land Claims, 1886-1930 | 3,310 |
| Maine, U.S., Revolutionary War Land Grants, 1776-1780 | 2,679 |
| Native Soil Manuscripts Index | 2,356 |
| U.S., Identification Card Files of Prohibition Agents, 1920-1925 | 1,772 |
| Maine, U.S., Revolutionary War Bounty Applications, 1835-1836 | 1,483 |
| Minutes of the court of Albany, Rensselaerswyck and Schenectady | 1,474 |
| English Origins of New England Families, Second Series Vol. II | 1,046 |
| English Origins of New England Families, Second Series Vol. III | 997 |
| Maine Wills, 1640-1760 | 962 |
| English Origins of New England Families, Vol. III | 883 |
| English Origins of New England Families, Vol. II | 845 |
| Minutes of the court of Fort Orange and Beverwyck | 652 |
| Alleged frauds against certain Indian soldiers | 590 |
| The Mayflower Reader | 530 |
| History of York, Maine, Vol. I | 476 |
| Lincoln County, Maine, Probate Records, 1760-1800 | 453 |
| History of York, Maine, Vol. II | 433 |
| The Tichborne romance | 429 |
| American Wills and Administrations | 423 |
| Record of Indentures [1771-1773] | 362 |
| The Maine register and business directory for the year 1856 | 360 |
| Family record of the Henderson and Whiddon families and their descendants | 316 |
| English Origins of American Colonists | 294 |
| The government of Maine : its history and administration | 279 |
| The Pioneers of Maine and New Hampshire, 1623-1660 | 259 |
| Fifty Puritan ancestors, 1628-1660 : genealogical notes, 1560-1900 | 230 |
| Collections for a genealogy of the noble families of Henzey, Tyttery, and Tyzack (De Hennezel, De Thiétry, and Du Thisac) | 218 |
| U.S., Album of Criminals, 1906 | 203 |
| Records of the Halls of Wallingford and the Buckinghams of Milford | 166 |
| La familia de Sor Juana Ines de la Cruz : documentos inéditos | 158 |
| The Unton inventories, relating to Wadley and Faringdon, Co. Berks., in the years 1596 and 1620 | 142 |
| A Calendar of the White Collection of Manuscripts in the Public Archives of Nova Scotia | 140 |
| English Estates of American Settlers | 109 |
| Carter | 109 |
| Calendar of "Parsons" wills and administrations (Prerogative Court of Canterbury, &c., Somerset House, London) : from A.D. 1417 | 109 |
| Early wills illustrating the ancestry of Harriot Coffin : with genealogical and biographical notes | 90 |
| Family data relating to Fouts, Yount, Taylor & Hoovers | 87 |
| To the descendants of Timothy Ingraham : information respecting the great Ingraham estate in the kingdom of Great Britain | 81 |
| The Records of the Cranston family | 74 |
| Land titles in old Pittston | 56 |
| Division of Abington: closing argument of Hon. Ellis W. Morton before the Committee of the Legislature on Towns | 50 |
| Early town records of Newcastle, Maine, from June 24, 1756, to January 6, 1779 | 49 |
| Abstracts of the wills of the Mather family | 39 |
| Addenda to items of ancestry | 38 |
| Dew wills and administrations : in the Prerogative Court of Canterbury | 37 |
| Edward Washington and his kin | 37 |
| 1902 Kingfield register | 34 |
| Report of the executive board of the Friends' Association of Philadelphia and Its Vicinity, for the Relief of Colored Freedmen | 32 |
| Extracts from British archives on the families of Halley, Hawley, Pyke, etc. | 32 |
| A pedigree & genealogical notes, from wills, registers, and deeds of the highly distinguished family of Penn. | 29 |
| U.S., American Protective League Correspondence, 1917-1919 | 24 |
| Will of Samuel St. John, 1844 | 23 |
| Copies of public records re William Huddleston land grant | 20 |
| Forbes family information | 20 |
| Facts about the Carroll County Kearsarge Mountain of New Hampshire | 18 |
| Halleian miscellany. | 16 |
| Abstracts of wills and administration papers | 15 |
| Botts family data | 13 |
| This plan of Kennebeck & Sagadahock Rivers & country adjacent | 7 |
| A centennial law suit | 3 |