Yes, a Jira board can have multiple projects. The Jira board feature allows you to view and manage work across multiple projects in a single view. You can create multiple boards, each containing specific projects that you wish to monitor. You can also CLone an existing board, so that its current state serves as the basis for future tasks to take on.
The boards can be divided by sprints, releases, projects, tasks, and any other criteria that you choose. You also have the ability to add metrics to your board, giving you insight into the progress of the task or project, which makes it easy to aggregate work from multiple projects into one view.
In addition, you can use Jira's advanced filters to create custom filters for a board. This allows you to customize your board with specific criteria, such as the component, the people assigned to tasks, the workflow status, and more. This way, you can make sure that everyone on the team is working on the right task at any given moment.
Overall, Jira boards offer organizations the ability to have complete visibility into multiple projects, while still seeing the overall progress at any given time. This makes it easier to manage multiple projects, ensuring that everyone is on the same page.