Historic Oil Field
On June 23, 1921, the Alamitos No. 1 well roared in atop Signal Hill, and the Long Beach field was born — historically the richest oil field per acre the world had seen. Derricks packed the hill so densely it was nicknamed "Porcupine Hill," and in 1923 the field produced over 68 million barrels in a single year. Cumulative production approaches a billion barrels from an area of only a few square miles. Today Signal Hill Petroleum operates the remaining wells among the homes and businesses of the city of Signal Hill.
Shell drilled Alamitos No. 1 on a hilltop that rival geologists had dismissed, and its gusher on June 23, 1921 set off perhaps the most frenzied urban oil boom in American history. Signal Hill had already been subdivided into house lots, so thousands of small landowners became lessors and fractional royalty owners overnight — a legacy that still shapes ownership in the field a century later.
By 1923 the field led the world, producing over 68 million barrels that year and helping make California the source of roughly a quarter of global oil output. Wells stood legs-to-legs across "Porcupine Hill," draining stacked sands thousands of feet down the sharp anticline. The inevitable decline followed, but the field’s per-acre recovery remained without historical equal.
The modern era belongs to Signal Hill Petroleum, the independent that consolidated most of the field’s operations beginning in the 1980s and has since run production alongside — and underneath — the redeveloped city, using directional drilling from consolidated sites and waterflood support in mature zones. The company has also conducted modern 3D seismic surveys beneath the urban footprint in search of remaining reserves.
The Long Beach field drapes over a sharp, faulted anticline on the Newport-Inglewood fault zone — the hill itself is the structure’s surface expression. Production comes from stacked Miocene and Pliocene sands, including the shallow Alamitos zone and the deeper Brown and associated zones, at depths from under 3,000 to more than 7,000 feet. The trap’s tight closure and thick, oil-charged section on a small surface area produced the field’s extraordinary richness per acre. The same fault zone generated the destructive 1933 Long Beach earthquake.
Recovery in the field’s later life has depended on waterflooding: injected water supports pressure in sands that six decades of intense production depleted, sweeping remaining oil to wells now drilled directionally from a handful of consolidated urban sites. For royalty owners, waterflood support and modern reservoir mapping are what keep century-old zones paying. Operations proceed under CalGEM permitting with the added constraints of a fully built-out city — including California’s setback rules for new wells near homes — which channels activity into redrills and optimization on existing sites rather than expansion.
Signal Hill royalties are heirlooms of the 1920s boom — often small decimals descended through several generations from a single house lot. They still pay, because a focused operator continues to invest in a structure that rewarded owners for a century. Valuing them takes patience with old leases, community lot pooling, and fractional title — work many buyers will not do, which depresses casual offers. We do that work and price the interest on its actual wells. We buy minerals and royalties in Los Angeles County and provide free written offers.
County-level well data, production charts, and selling guides for the counties this field spans:
Because many tiny decimals add up to a field, buyers who work in this area value small fractions seriously. A long-paying interest, however small, has a computable present value, and consolidating fractions has value to buyers in itself. A free written offer tells you the real number.
The large majority of the field has been operated for decades by Signal Hill Petroleum, an independent based in the city itself. Your check stub confirms the payor for your particular lease or unit — the anchor fact for any evaluation.
Typically a chain from the original lot lease or royalty deed through probates or affidavits of heirship to you, plus a current check stub if the interest pays. Gaps are common after a century, and we routinely help owners cure them as part of preparing a written offer.