A modular irrigation controller includes a processor capable of executing a stored watering program and controlling a plurality of removable station modules in accordance with the watering program. Each station module includes a station module circuit for opening and closing a plurality of valves. A plurality of connectors can mate each mate to establish a communications link between the station modules and the processor. A plurality of terminals are each connectable with a corresponding one of a plurality of field valve lines from the valves. The terminals are mounted separate from the station modules and are connected to the connectors. This allows the irrigation controller to have a more compact design, provides connection terminals for spare field valve lines, and eliminates malfunctions due to erroneous re-connection of field valve lines during station module replacement.