The history of this site goes back to the construction of the Union Wharf in 1855. Considered locally to be the first railroad in the state, the track was built by the Union Plank Walk, Railtrack and Wharf Co. and extended from the rear of this block to deep water near the foot of I Street. Pilings from that wharf and railroad are still visible in the recreation lake at the Arcata Marsh. This early railroad consisted of pine rails and the motive power was a single horse. The Humboldt Times recorded the first railroad accident in 1856 when the "locomotive" was thrown from the track after her reins became entangled in the wheel while pulling a car loaded with passengers from the Plaza to the wharf. The original depot was replaced in 1887 with a new passenger depot which faced 7th Street at the northwest comer of 7th and H and a freight warehouse which extended to this comer. Expansion of the railroad to the Dolly Varden and Jolly Giant mills north of Arcata in the 1870's established a major transportation network for moving lumber from the mills to deep water where it was shipped to San Francisco and, in some cases, to overseas ports. In later years the depot and warehouse were used by Brizards for its tractor repair department and feed and seed warehouse, and by Pickwick Stage Co., Greyhound Bus Co. and McConnaha's Humboldt Motor Stages as a depot. The Post Office was built in 1950.