An electrical interconnection system with high speed, high density electrical connectors. One of the connectors includes a mating contact portion that generates contact force as it is compressed against a wall of the connector housing. The mating contact portion has multiple segments, each with a contact region extending from the wall, such that multiple points of contact to a complementary mating contact portion in a mating connector are provided for mechanical robustness. Additionally, each signal path through the mating interface portions of the connectors can be narrow and has a relatively uniform cross section to provide a uniform impedance. Additional size reduction may be achieved by mounting a ground contact on an exterior surface of a connector housing in alternating rows. Additionally, embodiments in which a wavy contact is used in a cantilevered configuration are also described.