The extent methods largely ignore the importance of integrating security requirements with business requirements and providing built-in steps for dealing with these requirements seamlessly. To address this problem, a new approach to secure network analysis and design is presented. The proposed method, called the SEACON method, provides an integrated approach to use existing principles of information systems analysis and design with the unique requirements of distributed secure network systems. We introduce several concepts including security adequacy level, process-location-security matrix, data-location-security matrix, and secure location model to provide built-in mechanisms to capture security needs and use them seamlessly throughout the steps of analyzing and designing secure networks. This method is illustrated and compared to other secure network design methods. The SEACON method is found to be a useful and effective method.