Two possible planetary nebulae ( PN G035.5-00.4 and IRAS 18551+0159 ) , one newly re-identified supernova remnant ( SNR G35.6-0.4 ) , and one Hii region ( G35.6-0.5 ) form a line-of-sight-overlapped complex known as G35.6-0.5 .
We analyze 21 cm Hi absorption spectra towards the complex to constrain their kinematic distances .
PN G035.5-00.4 has a distance from 3.8 \pm 0.4 kpc to 5.4 \pm 0.7 kpc .
IRAS 18551+0159 is at 4.3 \pm 0.5 kpc .
We discuss the distance for SNR 35.6-0.4 , for which the previous estimate was 10.5 kpc , and find plausible for it to be 3.6 \pm 0.4 kpc .
The new distance of SNR G35.6-0.4 and the derived mass for the \sim 55 km s ^ { -1 } CO molecular cloud can accommodate an association with HESS J1858+020 .
We also conclude that SNR G35.6-0.4 is unlikely associated with PSR J1857+0210 or PSR J1857+0212 , which are projected into the SNR area .