1. Create a Record Query.
2. On the Criteria tab select Record, Record ID, operator not blank.
3. On the Output tab, select Record, Record ID and all other appropriate fields.
4. On the Sort tab, select Record, Record ID.
5. Click the Descending button at the bottom of Sort tab.
6. Select the Results tab.

The first Record ID that appears is the most recently used Record ID.

OR

1. Create a Record Query.
2. On the Criteria tab select Record Properties, Date Added, operator greater than, and choose a date when the last records were added.
3. On the Output tab, select Record, Record ID and all other appropriate fields.
4. On the Sort tab, select Query Fields, date added
5. Click the Descending button at the bottom of Sort tab.
6. Select the Results tab.