Below is a chronological listing of the United States senators from Delaware. U.S. senators were originally elected by the Delaware General Assembly for designated six-year terms beginning on March 4. Frequently portions of the term would remain only upon a U.S. senator's death or resignation. From 1914 and the enforcement of the Seventeenth Amendment to the United States Constitution, adopted in 1913 but rejected by the General Assembly that year and not ratified until July 1, 2010, officeholders were popularly elected on the first Tuesday after November 1; starting 1935, the beginning of their term is January 3.
Delaware's current U.S. senators are Democrats Chris Coons (serving since November 15, 2010) and Lisa Blunt Rochester (serving since January 3, 2025). Joe Biden is Delaware's longest serving senator (1973–2009). Delaware is one of eighteen states alongside California, Colorado, Georgia, Hawaii, Idaho, Louisiana, Maine, Massachusetts, Minnesota, Missouri, Nevada, Oklahoma, Pennsylvania, South Carolina, South Dakota, Utah, and West Virginia, to have a younger senior senator and an older junior senator.
List of senators
|- style="height:2em" ! rowspan=3 | 1 | rowspan=3 align=left | George Read | rowspan=3 | Pro-Admin. | rowspan=3 nowrap | Mar 4, 1789 –Sep 18, 1793 | Elected in 1788. | 1 | | rowspan=2 | 1 | rowspan=2 | Elected in 1788. | rowspan=2 nowrap | Mar 4, 1789 –Mar 3, 1793 | | Anti-Admin. | rowspan=2 align=right | Richard Bassett ! rowspan=2 | 1
|- style="height:2em" | rowspan=2 | Re-elected in 1790.Resigned to become Chief Justice of Delaware. | rowspan=5 | 2 | | | Pro-Admin.
|- style="height:2em" | rowspan=3 | rowspan=8 | 2 | rowspan=5 | Elected in 1793.Resigned. | rowspan=5 nowrap | Mar 4, 1793 –Jan 19, 1798 | rowspan=3 | Pro-Admin. | rowspan=5 align=right | John Vining ! rowspan=5 | 2
|- style="height:2em" | colspan=3 | Vacant | nowrap | Sep 18, 1793 –Feb 7, 1795
|- style="height:2em" ! rowspan=7 | 2 | rowspan=7 align=left | Henry Latimer | | Pro-Admin. | rowspan=7 nowrap | Feb 7, 1795 –Feb 28, 1801 | rowspan=2 | Elected in 1795 to finish Read's term.
|- style="height:2em" | rowspan=6 | Federalist | | rowspan=2 | Federalist
|- style="height:2em" | rowspan=5 | Re-elected in 1797.Resigned. | rowspan=7 | 3 | rowspan=4
|- style="height:2em" | Elected in 1798 to finish Vining's term.Died. | nowrap | Jan 19, 1798 –Aug 11, 1798 | | Federalist | align=right | Joshua Clayton ! 3
|- style="height:2em"
| nowrap | Aug 11, 1798 –Jan 17, 1799 | colspan=3 | Vacant
|- style="height:2em" | Elected in 1799 to finish Clayton's term. | rowspan=5 nowrap | Jan 17, 1799 –Nov 6, 1804 | rowspan=5 | Federalist | rowspan=5 align=right | William H. Wells ! rowspan=5 | 4
|- style="height:2em" | rowspan=2 | rowspan=6 | 3 | rowspan=4 | Re-elected in 1799.Resigned.
|- style="height:2em" ! rowspan=8 | 3 | rowspan=8 align=left | Samuel White | rowspan=8 | Federalist | rowspan=8 nowrap | Feb 28, 1801 –Nov 4, 1809 | rowspan=2 | Appointed to finish Latimer's term.
|- style="height:2em"
|- style="height:2em" | rowspan=5 | Re-elected in 1803., citing Journal of the Delaware State Senate, 1803. 13–14. | rowspan=5 | 4 | rowspan=3
|- style="height:2em"
| nowrap | Nov 6, 1804 –Nov 13, 1804 | colspan=3 | Vacant
|- style="height:2em" | Elected in 1804 to finish Wells's term. | rowspan=7 nowrap | Nov 13, 1804 –Mar 3, 1813 | rowspan=7 | Federalist | rowspan=7 align=right | James A. Bayard ! rowspan=7 | 5
|- style="height:2em" | | rowspan=5 | 4 | rowspan=5 | Re-elected in 1805.
|- style="height:2em"
|- style="height:2em" | Re-elected in 1809., citing United States' Gazette (Philadelphia, PA). January 14, 1809.
Died. | rowspan=6 | 5 | rowspan=3
|- style="height:2em" | colspan=3 | Vacant | nowrap | Nov 4, 1809 –Jan 12, 1810
|- style="height:2em" ! rowspan=7 | 4 | rowspan=7 align=left | Outerbridge Horsey | rowspan=7 | Federalist | rowspan=7 nowrap | Jan 12, 1810 –Mar 3, 1821 | rowspan=4 | Elected in 1810 to finish White's term.
|- style="height:2em" | | rowspan=4 | 5 | Re-elected in 1811.Resigned.
|- style="height:2em" | rowspan=2
| nowrap | Mar 3, 1813 –May 21, 1813 | colspan=3 | Vacant
|- style="height:2em" | rowspan=2 | Elected in 1813 to finish Bayard's term.Retired. | rowspan=2 nowrap | May 21, 1813 –Mar 3, 1817 | rowspan=2 | Federalist | rowspan=2 align=right | William H. Wells ! rowspan=2 | 6
|- style="height:2em" | rowspan=3 | Re-elected in 1815., citing Journal of the Delaware House of Representatives, 1815. 37.Retired. | rowspan=3 | 6
|- style="height:2em" | | rowspan=5 | 6 | rowspan=5 | Elected in 1817.Legislature failed to elect. | rowspan=5 nowrap | Mar 4, 1817 –Mar 3, 1823 | rowspan=5 | Federalist | rowspan=5 align=right | Nicholas Van Dyke ! rowspan=9 | 7
|- style="height:2em"
|- style="height:2em" | colspan=3 | Vacant | nowrap | Mar 4, 1821 –Jan 23, 1822
| rowspan=10 | 7 | rowspan=3
|- style="height:2em" ! 5 | align=left | Caesar A. Rodney | | Democratic-Republican | nowrap | Jan 24, 1822 –Jan 29, 1823 | Elected late to finish vacant term.Resigned to become U.S. Minister to the United Provinces of the River Plate.
|- style="height:2em" | rowspan=3 colspan=3 | Vacant | rowspan=3 nowrap | Jan 29, 1823 –Jan 8, 1824 | rowspan=3 |
|- style="height:2em" | rowspan=3 | rowspan=8 | 7
| nowrap | Mar 4, 1823 –Jan 8, 1824 | colspan=2 | Vacant
| rowspan=3 | Re-elected late.Died. | rowspan=3 nowrap | Jan 8, 1824 –May 21, 1826 | rowspan=2 | Federalist | rowspan=3 align=right | Nicholas Van Dyke
|- style="height:2em" ! rowspan=5 | 6 | rowspan=5 align=left | Thomas Clayton | | Federalist | rowspan=5 nowrap | Jan 8, 1824 –Mar 3, 1827 | rowspan=5 | Elected in 1824 to finish Rodney's term.
|- style="height:2em" | rowspan=4 | NationalRepublican | rowspan=4 | | NationalRepublican
|- style="height:2em"
| nowrap | May 21, 1826 –Nov 8, 1826 | colspan=3 | Vacant
|- style="height:2em" | Appointed to continue Van Dyke's term.Retired. | nowrap | Nov 8, 1826 –Jan 12, 1827 | | NationalRepublican | align=right | Daniel Rodney ! 8
|- style="height:2em" | rowspan=2 | Elected in 1827 to finish Van Dyke's term.Retired. | rowspan=2 nowrap | Jan 12, 1827 –Mar 3, 1829 | rowspan=2 | Jacksonian | rowspan=2 align=right | Henry M. Ridgely ! rowspan=2 | 9
|- style="height:2em" ! rowspan=2 | 7 | rowspan=2 align=left | Louis McLane | rowspan=2 | Jacksonian | rowspan=2 nowrap | Mar 4, 1827 –Apr 16, 1829 | rowspan=2 | Elected in 1827.Resigned to become U.S. Envoy Extraordinary and Minister Plenipotentiary to England. | rowspan=5 | 8
|- style="height:2em" | rowspan=3 | rowspan=5 | 8 | rowspan=5 | Elected in 1829. | rowspan=7 nowrap | Mar 4, 1829 –Dec 29, 1836 | rowspan=7 | NationalRepublican | rowspan=7 align=right | John M. Clayton ! rowspan=7 | 10
|- style="height:2em" | colspan=3 | Vacant | nowrap | Apr 16, 1829 –Jan 7, 1830
|- style="height:2em" ! rowspan=4 | 8 | rowspan=4 align=left | Arnold Naudain | rowspan=4 | NationalRepublican | rowspan=4 nowrap | Jan 7, 1830 –Jun 16, 1836 | rowspan=2 | Elected in 1830 to finish McLane's term.
|- style="height:2em"
|- style="height:2em" | rowspan=2 | Re-elected in 1832.Resigned. | rowspan=6 | 9
|- style="height:2em" | rowspan=4 | rowspan=8 | 9 | rowspan=2 | Re-elected in 1835.Resigned.
|- style="height:2em" ! rowspan=9 | 9 | rowspan=5 align=left | Richard H. Bayard | rowspan=3 | NationalRepublican | rowspan=5 nowrap | Jun 17, 1836 –Sep 19, 1839 | rowspan=4 | Elected in 1836 to finish Naudain's term.
|- style="height:2em"
| nowrap | Dec 29, 1836 –Jan 9, 1837 | colspan=3 | Vacant
|- style="height:2em" | rowspan=5 | Elected in 1837 to finish his cousin's term. | rowspan=8 nowrap | Jan 9, 1837 –Mar 3, 1847 | | NationalRepublican | rowspan=8 align=right | Thomas Clayton ! rowspan=8 | 11
|- style="height:2em" | rowspan=2 | Whig | | rowspan=7 | Whig
|- style="height:2em" | Re-elected during the 1838/39 cycle.Resigned to become Chief Justice of Delaware. | rowspan=5 | 10 | rowspan=3
|- style="height:2em" | colspan=2 | Vacant | nowrap | Sep 19, 1839 –Jan 11, 1841
|- style="height:2em" | rowspan=3 align=left | Richard H. Bayard | rowspan=3 | Whig | rowspan=3 nowrap | Jan 12, 1841 –Mar 3, 1845 | rowspan=3 | Elected in 1841 to finish his own term.Retired.
|- style="height:2em" | | rowspan=3 | 10 | rowspan=3 | Re-elected in 1841.
|- style="height:2em"
|- style="height:2em" ! rowspan=2 | 10 | rowspan=2 align=left | John M. Clayton | rowspan=2 | Whig | rowspan=2 nowrap | Mar 4, 1845 –Feb 23, 1849 | rowspan=2 | Elected in 1845.Resigned to become U.S. Secretary of State. | rowspan=4 | 11
|- style="height:2em" | rowspan=2 | rowspan=4 | 11 | rowspan=4 | Elected in 1846 or 1847.Retired. | rowspan=4 nowrap | Mar 4, 1847 –Mar 3, 1853 | rowspan=4 | Whig | rowspan=4 align=right | Presley Spruance ! rowspan=4 | 12
|- style="height:2em" ! rowspan=2 | 11 | rowspan=2 align=left | John Wales | rowspan=2 | Whig | rowspan=2 nowrap | Feb 23, 1849 –Mar 3, 1851 | rowspan=2 | Elected in 1849 to finish Clayton's term.Lost re-election.
|- style="height:2em"
|- style="height:2em" ! rowspan=10 | 12 | rowspan=10 align=left | James A. Bayard Jr. | rowspan=10 | Democratic | rowspan=10 nowrap | Mar 4, 1851 –Jan 29, 1864 | rowspan=6 | Elected in 1851. | rowspan=6 | 12
|- style="height:2em" | | rowspan=6 | 12 | rowspan=2 | Elected in 1853.Died. | rowspan=2 nowrap | Mar 4, 1853 –Nov 9, 1856 | rowspan=2 | Whig | rowspan=2 align=right | John M. Clayton ! rowspan=2 | 13
|- style="height:2em" | rowspan=4
|- style="height:2em"
| nowrap | Nov 9, 1856 –Nov 19, 1856 | colspan=3 | Vacant
|- style="height:2em" | Appointed to continue Clayton's term.Declined nomination to finish Clayton's term. | nowrap | Nov 19, 1856 –Jan 14, 1857 | | Whig | align=right | Joseph P. Comegys ! 14
|- style="height:2em" | rowspan=2 | Elected in 1857 to finish Clayton's term.Lost re-election. | rowspan=2 nowrap | Jan 14, 1857 –Mar 3, 1859 | rowspan=2 | Democratic | rowspan=2 align=right | Martin W. Bates ! rowspan=2 | 15
|- style="height:2em" | rowspan=3 | Re-elected in 1857. | rowspan=3 | 13
|- style="height:2em" | | rowspan=4 | 13 | rowspan=4 | Elected in 1858. | rowspan=9 nowrap | Mar 4, 1859 –Mar 3, 1871 | rowspan=9 | Democratic | rowspan=9 align=right | Willard Saulsbury Sr. ! rowspan=9 | 16
|- style="height:2em"
|- style="height:2em" | Re-elected in 1863.Resigned. | rowspan=6 | 14 | rowspan=2
|- style="height:2em" ! rowspan=3 | 13 | rowspan=3 align=left | George R. Riddle | rowspan=3 | Democratic | rowspan=3 nowrap | Jan 29, 1864 –Mar 28, 1867 | rowspan=3 | Elected in 1864 to finish Bayard's term.Died.
|- style="height:2em" | | rowspan=5 | 14 | rowspan=5 | Re-elected in 1864.Lost re-election.
|- style="height:2em" | rowspan=3
|- style="height:2em" | colspan=3 | Vacant | nowrap | Mar 29, 1867 –Apr 5, 1867
|- style="height:2em" ! 14 | align=left | James A. Bayard Jr. | | Democratic | nowrap | Apr 5, 1867 –Mar 3, 1869 | Appointed to continue his own term.Elected in 1869 to finish his own term.Byrd & Wolff, p. 90.Retired.
|- style="height:2em" ! rowspan=9 | 15 | rowspan=9 align=left | Thomas F. Bayard | rowspan=9 | Democratic | rowspan=9 nowrap | Mar 4, 1869 –Mar 6, 1885 | rowspan=3 | Elected in 1869. | rowspan=3 | 15
|- style="height:2em" | | rowspan=3 | 15 | rowspan=3 | Elected in 1870. | rowspan=11 nowrap | Mar 4, 1871 –Mar 3, 1889 | rowspan=11 | Democratic | rowspan=11 align=right | Eli Saulsbury ! rowspan=11 | 17
|- style="height:2em"
|- style="height:2em" | rowspan=3 | Re-elected in 1875. | rowspan=3 | 16
|- style="height:2em" | | rowspan=3 | 16 | rowspan=3 | Re-elected in 1876.
|- style="height:2em"
|- style="height:2em" | rowspan=3 | Re-elected in 1881.Resigned to become U.S. Secretary of State. | rowspan=5 | 17
|- style="height:2em" | | rowspan=5 | 17 | rowspan=5 | Re-elected in 1883.Lost re-election.
|- style="height:2em" | rowspan=3
|- style="height:2em" | colspan=3 | Vacant | nowrap | Mar 6, 1885 –Mar 18, 1885