Penryn is a census-designated place in Placer County, California, in the United States. Geographic location is 38°51′08″N 121°10′06″W / 38.85222°N 121.16833°W / 38.85222; -121.16833. Penryn is located 5.5 miles (8.9 km) northeast of Rocklin. The community's ZIP code is 95663 and the area code 916. The population was 831 at the 2010 census.
The story of Penryn begins in late 1864 when a Welsh immigrant by the name of Griffith Griffith established a granite quarry on quarter section of land leased from the Central Pacific Railroad. A siding was completed on February 6, 1865, and the first load of cut stone was shipped less than a week later. The quarry was open for business, but as yet, had no name. The railroad, matter-of-factly, designated the siding “Griffith’s Granite Station,” but Griffith had something else in mind.
Back home in North Wales, G. G., like his father before him, worked in the Penrhyn Slate Quarry. In Welsh, the word penrhyn translates to headland or promontory, which aptly described the seaport from which the Penrhyn Quarry took its name. When it came to naming his new enterprise, the choice was obvious, but not the spelling. To simplify things and avoid the inevitable misspellings that were likely to occur, on the evening of May 17, 1865, Griffith, after discussing the matter with Central Pacific legal counsel Edwin Bryant Crocker (known later for the Crocker Art Museum), agreed to drop the “h” from the original Welsh spelling and settled on the name, and spelling, we know today. The following day, Griffith recorded this auspicious event in his diary: “Concluded last night with Judge Crocker to call this quarry Penryn.”