| C/1913 Y1 (Delavan) | |
| Discoverer: | Pablo T. Delavan |
| Discovery Site: | La Plata Observatory |
| Discovery Date: | 18 December 1913 |
| Designations: | 1913f 1914 V |
| Epoch: | 15 March 1914 (JD 2420206.5) |
| Observation Arc: | 628 days (1.72 years) |
| Obs: | 1006 |
| Perihelion: | 1.1044 AU |
| Eccentricity: | 1.00014 |
| Inclination: | 68.043° |
| Asc Node: | 60.397° |
| Arg Peri: | 287.436° |
| Earth Moid: | 0.63832 AU |
| Jupiter Moid: | 1.64685 AU |
| M1: | 4.8 |
| Last P: | 26 October 1914 |
Comet Delavan, formally designated as C/1913 Y1, is a hyperbolic comet discovered by astronomer Pablo T. Delavan on December 18, 1913, from the La Plata Observatory in Argentina.
The comet was last seen on September 19, 1915. It is one of 19 comets used in the original sample by Jan Oort for his hypothesis regarding the origin of long-period comets in 1950.