Parallax
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One the parallax angle is known, a trignometry calculation gives the distance to a star. Although the triangles are very thin, the calculation is the same as for finding distances on Earth or to the Moon. Details.
The first stellar parallax was measured in 1838 when Bessel applied advances in mathematics and precision observing equipment to the task. Over the next 150 years, many of the nearer stars were located and the distances to them measured. The CNS3 catalog, 1991 lists parallaxes for 3,803 nearby stars measured by observatories around the world. Between 1989 and 1993, the Hipparcos Satellite measured the parallaxes of over a million stars. Web address: Hipparcos Home Page