The Human Services Agency of Ventura County has leased 57,200 square feet at Younan Executive Center in Simi Valley, in what is said to be the largest single lease so far this year in Ventura County.

The transaction brings the 2900 Madera Road building to full occupancy one year after it was acquired without any tenants by Younan Properties Inc., a Woodland Hills-based real estate investment and management firm, according to the LA North/Ventura office of Lee & Associates, which represented the landlord.

The Younan Executive Center is a two-story, 63,305-square-foot Class A office building. The social services agency expects to bring 150 employees to the center.

“The building had been completely vacant for four years. This is a significant, long-term lease with a major tenant,” said Younan Properties Chief Executive Zaya Younan in a statement.

Mark T. Leonard, senior vice president and principal, and Cory Richmond and Jared Smits, vice presidents, handled the landlord representation for Lee & Associates. The tenant was represented in-house by Keith Filegar, manager of real estate services division for Ventura County.