Data are reported on the radioactivity of environmental samples collected from locations within the Hanford plant boundaries during the last six months of 1969. Data are included on: the total alpha activity and content of / sup 90/Sr and tritium in samples of Columbia River water; the total BETA activity of samples of drinking water; the total alpha , BETA , and gamma activity of samples of surface wnters; the total BETA activity and /sup 131/I content of samples of surface air; and the total alpha , BETA , and gamma activity and content of /sup 95/Zr, /sup 106/Ru, /sup 134/Cs, /sup 137/Cs, /sup 140/Ba, /sup 144/Ce, /sup 238/Pu, /sup 239/Pu and /sup 240/Pu of air filter samples. Est imates were made of the average external gamma - radiation exposure rates of personnel. (CH)