  Using data from the Galactic Arecibo L-band Feed Array Continuum Transit
Survey (GALFACTS), we report the discovery of two previously unidentified, very
compressed, thin, and straight polarized filaments approximately centred at
Galactic coordinates, $(l,b)=(182.5^\circ,-4.0^\circ)$, which we call
G182.5--4.0. Using data from the Isaac Newton Telescope Galactic Plane Survey
(IGAPS), we also find straight, long, and extremely thin H$\alpha$ filaments
coincident with the radio emission. These filaments are positioned in
projection at the edge of the Orion-Eridanus superbubble and we find evidence
indicating that the filaments align with the coherent magnetic field of the
outer Galaxy. We find a lower limit on the total radio flux at 1.4~GHz to be
$0.7\pm0.3$~Jy with an average linearly polarized fraction of $40\substack{+30
\\ -20}\%$. We consider various scenarios that could explain the origin of
these filaments, including a shell-type supernova remnant (SNR), a bow shock
nebula associated with a pulsar, or relic fragments from one or more supernova
explosions in the adjacent superbubble, with a hybrid scenario being most
likely. This may represent an example of a new class of objects that is neither
an SNR nor a bow shock. The highly compressed nature of these filaments and
their alignment with Galactic plane suggests a scenario where this object
formed in a magnetic field that was compressed by the expanding Orion-Eridanus
superbubble, suggesting that the object is related to this superbubble and
implying a distance of $\sim$400~pc.
