This unit comes with a memory card inside the unit, there is no GPS slot to insert an SD card.

You would need to first install T4A GPS Maps on your computer and then send the maps via Garmins MapSource Software to the internal memory card of your GPS unit.

MapSource only works on windows. Garmins new software, BASECAMP, does not work with the 276C. But in order to make MapSource work on your computer, you would have to install BASECAMP first and then MapSource – this is the way Garmin works. Both software products are available for free from the Garmin website, just google ‘download BASECAMP’ and ‘download MapSource’ and be sure to download from the Garmin website.

You can then purchase our GPS maps electronically from our website, then install them on your computer and transfer them to your GPS unit. If you purchase the T4A SD card, the installation files are available on the SD card, under ‘PC Install Files’. Please refer to our FAQ for more assistance with using MapSource and BASECAMP.

If you have upgraded to Windows 11:

It is apparent that the device drivers in Win11 do not include that which is needed for the old 276c device. If you apply these steps, BASECAMP then seems to work with the 276C.

You can try this: Follow these steps:

1) Download the latest USB Drivers Software: Garmin: USB Drivers Updates & Downloads

2) Install the latest web updater: https://www8.garmin.com/support/download_details.jsp?id=931

after installing both of these and doing a restart, BASECAMP should now recognise the 276c (note Not the 276cx).