  We show that a gapped spin-$S$ chain with antiferromagnetic (AFM) order
exhibits in the thermodynamic limit exponentially localized fractional $\pm
\frac{S}{2}$ edge modes when the system possesses U(1) symmetry. We show this
for integrable and non integrable spin chains both analytically and
numerically. Through exact analytical solutions, we show that an AFM
spin-$\frac{1}{2}$ chain with {\it explicitly} broken $\mathbb{Z}_2$ symmetry
and an integrable AFM spin-$1$ chain with {\it spontaneously} broken
$\mathbb{Z}_2$ symmetry have $\pm \frac{1}{4}$ and $\pm \frac{1}{2}$
fractionalized edge modes, respectively. Furthermore, employing the density
matrix renormalization group technique, we extend this analysis to {\it
generic} $XXZ-S$ chains with $S\leq 3$ and demonstrate that these fractional
spins are robust quantum observables, substantiated by the observation of a
variance of the associated fractional spin operators that is consistent with a
vanishing functional form in the thermodynamic limit. Moreover, we find that
the edge modes are robust to disorder that couples to the N\'eel order
parameter.
