Picket Post House

Historic Building Fact Sheet

picketpost mansion

The historic Picket Post House as viewed from the main trail at the Boyce Thompson Arboretum. (Feb. 2024) Photo credit: Jake Case

Need to Know Info

AddressNorth Picket Post Road
Superior, Arizona
Coordinates33°16’42.09″N, -111°09’11.7″N
Date Added to NRHPMarch 26, 1976 (as part of Boyce Thompson Arboretum)

The Picket Post House was the 1920s winter estate of mining magnate William Boyce Thompson, situated dramatically on a cliff above the Boyce Thompson Arboretum he founded. The property was sold off in 1946, and changed ownership numerous times over the years.

In 1953, one of the house’s three structures (the Cliff House) was destroyed by a fire. In 2008 the property was reacquired by the Arboretum to be restored. Tours have not been offered at Picket Post House since 2019.

The In-Depth Story

The Picket Post House: William Boyce Thompson’s Elaborate Winter Home

Perched on a high cliff overlooking the Boyce Thompson Arboretum stands the Picket Post House, also known as the Picket Post Mansion. This dramatically situated estate served as the winter residence of William Boyce Thompson, the wealthy founder of the Arboretum.

William Boyce Thompson was a successful mining engineer who amassed a fortune from copper mining ventures in Arizona in the early 1900s. He established mining companies such as the Shannon Copper Company in Morenci and the Magma Mine in Superior. Thompson also created the prominent Newmont Mining Corporation. With his immense wealth, Thompson pursued philanthropic interests including improving agriculture and alleviating world hunger. In 1920 he founded the Boyce Thompson Institute for Plant Research in Yonkers, New York. A few years later, he established the Boyce Thompson Arboretum near Superior, Arizona, in 1924.

Seeking a winter home near his mining interests, Thompson chose a prominent spot overlooking the Arboretum property. Built between 1923 and 1929, the Picket Post House was designed by Thompson himself, modeled after a cliffside Greek monastery. Local contractor Jack Davey handled the construction, which took place in phases. The first section completed was the two-story Main House, with its red brick and stucco exterior. This contained a kitchen on the first floor and living spaces like the dining room and library upstairs.

Two other structures were later added in the Mediterranean Revival style. To the east sat the small stucco house of Thompson’s wife, Gertrude. To the south stood the most dramatic component, the three-story Cliff House. This wood-framed building with stucco finish housed Thompson’s private quarters. It was crowned by a rectangular water tower. The estate buildings featured details like thermae windows, red tile roofs, and extensions that made them seem built into the rocks. Thompson furnished the mansion with antiques and artwork from his European travels.

In 1928, Thompson donated the Picket Post House and surrounding land to the Arboretum. However, the high cost of upkeep proved too much, and the Arboretum sold the mansion in 1946. It passed through several owners, even serving as a bed and breakfast at one point. In 1953, the Cliff House was destroyed in a fire, leaving only the Main House and Gertrude’s House. In 2008, the surviving structures were acquired by Arizona State Parks and reunited with the Arboretum. Occasional public tours are now offered to help raise funds to restore the Picket Post House to its former glory. Though diminished, the dramatic cliffside estate still evokes the 1920s winter retreat of William Boyce Thompson.

NRHP Reference #: Unknown