I thought about asking a question regarding triggers in MS Access but wasn't sure if that belonged here or not.
I believe MS Access is on-topic as long as it is not about using the UI of Access. If you have a question about designing a DB in Access that would be fine.
I remember in college (I sound so old) that the first week or two of my first db class were taught using Access to get some of the basic concepts down before we dived into MySQL.
Besides dba.stackexchange.com is for all databases, not just the big three. There are some small businesses/projects that depend on MS Access.
Microsoft Office Access, previously known as Microsoft Access, is a pseudo-relational database management system from Microsoft that combines the relational Microsoft Jet Database Engine with a graphical user interface and software-development tools.
Just think about it, it has tables, triggers, views, etc. and you can use SQL on it. Sure, it's not a full-fledged, powerful DBMS, but as long as the questions are related to those database elements, of course it is on-topic.
I think they are on-topic. Here are two questions I asked on SO that now, I would ask here. I don't think they would have been on-topic for SU as @bigown suggests.
Off-topic and the OP's non-meta question is a good example of why.
As @Gan's answer quotes:
combines the [pseudo-]relational Microsoft Jet Database Engine with a graphical user interface and software-development tools
I would say that questions about the Microsoft Jet Database Engine are on-topic but those about the graphical user interface and other tools are off-topic (and on-topic for SU). The problem is that even experienced users of Access have problems seeing where the boundary between the two lies. For example, a simple question about a Jet SQL query may get a SQL answer which resembles a Jet SQL query but because it includes the
NZ() function it will error unless run within the Access user interface.
Going back to the OP's non-meta question about triggers, Access triggers are a feature of the Access user interface (or is it the other tools?) and are not part of Jet. The rule of thumb should be: can I create a trigger using SQL DML? The answer in this case is no, I need the Access UI/tool for this, therefore is off-topic for DBA.