Union Bay is an unincorporated community located south of Hart Creek[1] on the east coast of central Vancouver Island, British Columbia.

Prior to the 1780s smallpox epidemic, at least 3,000 Pentlatch people lived in more than 90 large villages and small settlements throughout the area.

Taking advantage of the decimation, the Lekwiltok (Euclataws), from an unaffected northern region, attacked with muskets, massacring and driving the K'ómoks south.

The 1946 Vancouver Island earthquake not only toppled chimneys in Union Bay, but also unearthed wooden posts in the sand and mud 15 kilometres (9 mi) north, evidencing a former Pentlatch presence.

During 2019–2020, excavations for a residential estate at the mouth of Hart (formerly Washer) Creek unearthed a number of Pentlatch human remains.

The 18-kilometre (11 mi) standard-gauge railway line, which included a long howe truss across the Trent River, was completed in 1889.

[18] During the two world wars Union Bay made a significant contribution in supplying fuel for allied freighters.

[19] Owned by Weldwood (now called West Fraser Timber),[11][21] the long abandoned coal wharf, with trees protruding through the trestle deck, was demolished in 1966.

[22] In 1896, the colliery erected a "Luhrig" coal washer, and completed 100 beehive coke ovens, using imported fire bricks.

Vandals had smashed the windows of offices, storage sheds, the powerhouse, and the machine shops that maintained the railway rolling stock.

Sidney Ryall bought the enterprise in 1948, while the surviving Horne family established a food market nearby.

One night in March 1913, while Wagner was burglarizing the Fraser & Bishop general store, two local police officers, Constables Westaway and Ross, confronted the pirate and his partner.

[33] At their Nanaimo trial, Wagner was sentenced to be hanged that August, and his accomplice, William Julian, received five years.

The next year, the Union Bay Improvement District (UBID) bought the property, which became subject to a legal action regarding its future use.

[19] By this time, offering the 200 inhabitants few job opportunities, Union Bay was considered a lifeless place counting on a pulp and paper mill proposal,[41] one of a series of industrial projects that never eventuated.

In 2020, Union Bay Estates (UBE), formerly known as Kensington Island Properties, broke ground at Hart Creek on a new subdivision to house at least 7,000 people (3,000 residences), with a proposed marina, hotels, and commercial district.

[42] The risk that toxic heavy metals, buried during the coal port era, could be released, contaminating the marine ecosystem of the Baynes Sound area, makes the development of a marina problematic.

[45] West Fraser Timber, the lessee, and the BC government, are carrying out remediation work on local coal hills.