Updating the Pre-Loaded Mapping on a GPSMAP 378

The GPSMAP 378 has a unique pre-loaded combination mapping. The mapping that this device is pre-loaded with is called Inland Detail with Roads. This is like a combination of our City Navigator NT and Inland Lakes mapping, however it is a combination of both instead of each being individually loaded into the device.

The Inland Detail with Roads mapping was discontinued in March of 2008 and we no longer offer map updates for that specific type of mapping.

Garmin no longer offers freshwater lake mapping on DVD. You may be able to find a copy of one one of our discontinued mapping products, U.S. Inland Lakes or Upper Midwest Fishing Guide. These maps can be installed on a computer and transferred to the GPSMAP 378.

To load the mapping to the portable chartplotter, a Garmin Data Card will need to be inserted into the device as the maps cannot be loaded to the internal memory of the device. The larger size of the card used, the more mapping can be stored. Garmin no longer sells Garmin Data Cards.

Once the mapping has been installed on the computer, insert the data card into the device and connect it to a PC using the provided USB cable. Select the areas of mapping you need and transfer them to the device. For a tutorial video on how to transfer the mapping to the device, please view the video tutorial at this link.