HENLEY-JOHNSTON & ASSOCIATES, INC., a privately owned Texas Corporation, was established to provide consulting geotechnical e ... ngineering and geosciences services from Dallas, Texas, over 70 years ago and is a leader and innovator in this highly specialized field of civil engineering and geology. Since inception, in 1951, the firm has provided engineering consulting and testing services in the professional fields of geotechnical engineering, engineering geology, geomechanics (soil and rock), foundation engineering, and construction materials engineering, inspection and testing. Henley-Johnston & Associates, Inc. (HJA) brings forth an unparalleled record of experience and achievement in working with major geologic formations underlying the greater northern Texas and southern Oklahoma subsurface region. read more