From Ingres Community Wiki

Links to all JDBC Driver downloads (both commercial and open source editions) can be found on this page.

New: The Ingres JDBC driver can be downloaded automatically when using Maven for dependency management. See Ingres JDBC With Maven for more details

JDBC Driver Downloads

The JDBC driver is bundled with the base ingres package under $II_SYSTEM/ingres/lib and is called iijdbc.jar.

GA versions of the Ingres JDBC Driver can be downloaded at http://esd.ingres.com/product/drivers/JDBC/java.

Community Preview (pre-GA) versions of the Ingres JDBC Driver can be downloaded at http://esd.ingres.com/product/Community_Projects/Drivers/java.