  This paper investigates the potential of near-field localization using
widely-spaced multi-subarrays (WSMSs) and analyzing the corresponding angle and
range Cram\'er-Rao bounds (CRBs). By employing the Riemann sum, closed-form CRB
expressions are derived for the spherical wavefront-based WSMS (SW-WSMS). We
find that the CRBs can be characterized by the angular span formed by the line
connecting the array's two ends to the target, and the different WSMSs with
same angular spans but different number of subarrays have identical normalized
CRBs. We provide a theoretical proof that, in certain scenarios, the CRB of
WSMSs is smaller than that of uniform arrays. We further yield the closed-form
CRBs for the hybrid spherical and planar wavefront-based WSMS (HSPW-WSMS), and
its components can be seen as decompositions of the parameters from the CRBs
for the SW-WSMS. Simulations are conducted to validate the accuracy of the
derived closed-form CRBs and provide further insights into various system
characteristics. Basically, this paper underscores the high resolution of
utilizing WSMS for localization, reinforces the validity of adopting the HSPW
assumption, and, considering its applications in communications, indicates a
promising outlook for integrated sensing and communications based on
HSPW-WSMSs.
