| Daniel Marcy | |
| State1: | New Hampshire |
| Term Start1: | March 4, 1863 |
| Term End1: | March 3, 1865 |
| Preceded1: | Gilman Marston |
| Succeeded1: | Gilman Marston |
| Office2: | Member of the New Hampshire Senate |
| Term2: | 1857-1858 |
| Office3: | Member of the New Hampshire House of Representatives |
| Term3: | 1854-1857 |
| Birth Date: | November 7, 1809 |
| Birth Place: | Portsmouth, New Hampshire, U.S. |
| Death Date: | November 3, 1893 (aged 83) |
| Death Place: | Portsmouth, New Hampshire, U.S. |
| Party: | Democratic |
Daniel Marcy (November 7, 1809 – November 3, 1893) was a United States representative from New Hampshire. He was born in Portsmouth, New Hampshire where he attended the common schools. Becoming a sailor, he followed the sea and later engaged in shipbuilding.
Marcy was a member of the New Hampshire House of Representatives 1854–1857. He also served in the New Hampshire Senate in 1857 and 1858. He was an unsuccessful candidate for election to the Thirty-sixth Congress in 1858 and to the Thirty-seventh Congress in 1860. However, he was elected as a Democrat to the Thirty-eighth Congress (March 4, 1863 – March 3, 1865). He was an unsuccessful candidate for reelection in 1864 to the Thirty-ninth Congress. After leaving Congress, he again served in the New Hampshire Senate in 1871 and 1872. He died in Portsmouth in 1893 and was buried in the Proprietors’ Burying Ground.