486958 Arrokoth (provisional designation 2014 MU69) is a trans-Neptunian object located in the Kuiper belt. Arrokoth became the farthest and most primitive object in the Solar System visited by a spacecraft when the NASA space probe New Horizons conducted a flyby on 1 January 2019. Arrokoth is a contact binary 36 km (22 mi) long, composed of two planetesimals 21 km (13 mi) and 15 km (9 mi) across, that are joined along their major axes. With an orbital period of about 298 years and a low orbital inclination and eccentricity, Arrokoth is classified as a cold classical Kuiper belt object.
Arrokoth was discovered on 26 June 2014 by astronomer Marc Buie and the New Horizons Search Team using the Hubble Space Telescope as part of a search for a Kuiper belt object for the New Horizons mission to target in its first extended mission; it was chosen over two other candidates to become the primary target of the mission.
Before its permanent name was announced, the object had previously been nicknamed Ultima Thule and Snowman.