Essex Agreement

ESSEX AGREES TO ACQUIRE PERFORMANCE GROUP, INC.
COLUMBIA, MD - June 07, 2004

Exhibit 99.1

- Essex Corporation (NASDAQ: KEYW), announces that it has entered into a definitive agreement to acquire Performance Group, Inc. (PGI) with main offices in Fredericksburg, Virginia. The acquisition is subject to customary closing conditions and is expected to close within the next several weeks. PGI is a privately owned company with 39 mployees, annual revenue of approximately $4.5 million in calendar year 2003, and profitable since it was founded in 1994. PGI provides services in the areas of Geographic Information Systems (GIS), Imagery Processing and Analysis, Spatial Data Development, Environmental Consulting, Visualization, and IT Solutions to government and private sector clients. Worldwide GIS revenues in 2003 are estimated by Daratech to have been $1.75 billion. "PGI is another excellent fit to our acquisition strategy," according to Leonard Moodispaw, CEO & President of Essex Corporation. "We create integrated solutions from our products, technologies, and services. PGI's strong GIS experience and capabilities will help us move toward 3-D imaging solutions by integrating 3-D Synthetic Aperture Radar images, produced by Essex proprietary technology, with industry leading GIS systems. By linking these images within a GIS system to a common geographic grid, the images can be combined with a wide range of other information to answer a wide range of difficult questions for both our intelligence & defense and commercial customers. We are excited to have the management and staff of PGI join our growing family of professionals." Mr. Ron Horn, President and Owner of PGI commented "Essex offers a winning combination of technology, resources, customer access, and corporate culture that will help PGI meet its full potential as a leading provider of GIS services and products. We are excited about the breakthrough technology potential of integrating the Essex 3-D imaging products with our GIS systems to produce an innovative new means of information analysis and presentation. We look forward to bringing new technology offerings from Essex to our current and expanded customer base. Of equal importance, Essex has a strong employee-focused culture that fits well with our culture at PGI and offers new and exciting opportunities for PGI's employees."