A well‐localized target of hydrogen, deuterium, or helium has been developed for use with the University of Illinois 300‐Mev betatron. The liquefied target gas is contained in a thin‐walled brass cylinder in contact with a low‐temperature reservoir. For hydrogen and deuterium targets the reservoir contains hydrogen, while for a helium target the reservoir contains helium. Target cylinders of 1.25‐inch diameter with 0.0005‐inch walls and 2‐inch and 4‐inch diameter with 0.001‐inch walls have been used giving proton and meson backgrounds from the cylinder walls of less than 10 percent. A liquid nitrogen cooled radiation shield surrounds the target and reservoir. The nitrogen shield and the vacuum jacket enclosing it have thin windows allowing one to study the production of protons of energy >20 Mev and mesons of energy >7 Mev. From the 3 liter reservoir the loss rate of liquid hydrogen is 40 ml per hour and of liquid helium is 250 ml per hour.