Penryn (Washo: Pénwin) 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 is in area codes 916 and 279. The population was 831 at the 2010 census.

What became Penryn began in late 1864 following a Welsh immigrant named Griffith Griffith customary 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 right to use 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 house in North Wales, Griffith, like his daddy 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 extra enterprise, the another 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 vanguard for the Crocker Art Museum), agreed to drop the “h” from the indigenous Welsh spelling and settled on the name, and spelling, we know today. The as soon as day, Griffith recorded this auspicious event in his diary: “Concluded last night in imitation of Judge Crocker to call this quarry Penryn.”

The quarry now had a name, but not the town, because there was no town, just the granite works and a railroad siding. Griffith’s employees all lived in the brusque area, so there were loads of people, but no businesses outside of what amounted to a small “company store” near the quarry. The nearest supply centers of any consequence were Newcastle and Smithville, near present-day Loomis. Griffith’s to the front ledgers book numerous transactions at both places.