  Superconducting nanowire single photon detectors (SNSPDs) are the
highest-performing technology for time-resolved single-photon counting from the
UV to the near-infrared. The recent discovery of single-photon sensitivity in
micrometer-scale superconducting wires is a promising pathway to explore for
large active area devices with application to dark matter searches and
fundamental physics experiments. We present 8-pixel $1 mm^2$ superconducting
microwire single photon detectors (SMSPDs) with $1\,\mathrm{\mu m}$-wide wires
fabricated from WSi and MoSi films of various stoichiometries using
electron-beam and optical lithography. Devices made from all materials and
fabrication techniques show saturated internal detection efficiency at 1064 nm
in at least one pixel, and the best performing device made from silicon-rich
WSi shows single-photon sensitivity in all 8 pixels and saturated internal
detection efficiency in 6/8 pixels. This detector is the largest reported
active-area SMSPD or SNSPD with near-IR sensitivity published to date, and the
first report of an SMSPD array. By further optimizing the photolithography
techniques presented in this work, a viable pathway exists to realize larger
devices with $cm^2$-scale active area and beyond.
