  As wireless networks evolve towards open architectures like O-RAN, testing,
and integration platforms are crucial to address challenges like
interoperability. This paper describes ARA-O-RAN, a novel O-RAN testbed
established through the NSF Platforms for Advanced Wireless Research (PAWR) ARA
platform. ARA provides an at-scale rural wireless living lab focused on
technologies for digital agriculture and rural communities. As an O-RAN
Alliance certified Open Testing and Integration Centre (OTIC), ARA launched
ARA-O-RAN -- the first public O-RAN testbed tailored to rural and agriculture
use cases, together with the end-to-end, whole-stack programmability. ARA-O-RAN
uniquely combines support for outdoor testing across a university campus,
surrounding farmlands, and rural communities with a 50-node indoor sandbox. The
testbed facilitates vital R\&D to implement open architectures that can meet
rural connectivity needs. The paper outlines ARA-O-RAN's hardware system
design, software architecture, and enabled research experiments. It also
discusses plans aligned with national spectrum policy and rural spectrum
innovation. ARA-O-RAN exemplifies the value of purpose-built wireless testbeds
in accelerating impactful wireless research.
