Cupertino, California, USA

Bill Hewlett and Dave Packard founded the well known company Hewlett-Packard or HP already in the year 1939 and started with an audio oscillator for test and measurement purposes. In the year 1968 HP introduces the world's first desktop scientific calculator, the HP 9100A.
In the same year they developed the first commercially available light-emitting diode (LED) found in the later electronic pocket calculators. Only 4 years later, spring 1972, HP makes another advance in personal computing with the HP-35, the world's first scientific handheld calculator. Today HP products are still known for their innovation and quality.

Source : Joerg Woerner, Datamath Calculator Museum