Oh most definitely made in Si Valley -- it was the first scientific pocket calculator, made to fit in Bill Hewlett's pocket.

If you got one of the very first ones, it has a bug in its log routine. As the story goes, Dave Packard insisted on revealing the bug's existence as soon as possible, and offering a replacement. But many people chose to live with the bug (it's minor). Like misprinted postage stamps and currency, the buggy HP-35 has become a collector's item among collector's items.