Coal combustion aerosol particles contribute to the concentrations of ice-nucleating particles (INPs) in the atmosphere. Especially, immersion freezing can be considered as one of the most important mechanisms for INP formation in supercooled tropospheric clouds that exist at temperatures between 0°C and -38°C. The U.S. contains more than 550 operating coal-burning plants consuming 7.2 x 10^8 metric tons of coal (in 2016) to generate a total annual electricity of >2 billion MW-h, resulting in the emission of at least 4.9 x 10^5 metric tons of PM10 (particulate matter smaller than 10 µm in diameter). In Texas alone, 19 combustion plants generate 0.15 billion MW-h electricity and >2.4 x 10^4 metric tons of PM10. Here we present the immersion freezing behavior of combustion fly ash and bottom ash particles collected in the Texas Panhandle region. Two types of particulate samples, namely <45 µm sieved bottom ash (B_Ash_TX_PH) and <45 µm sieved fly ash (F_Ash_TX_PH), were prepared. Afterwards, their immersion freezing abilities were measured using the Cryogenic Refrigerator Applied to Freezing Test (CRAFT) system covering the heterogeneous freezing temperature down to -30 °C. The results were generated and are reported through two metrics, frozen fraction, ffrozen(T), and ice nucleation active site density per unit mass, nm(T) as a function of temperature. Our preliminary results show that an onset increase in ffrozen(T) for B_Ash_TX_PH (ffrozen) occurred as high as at -15°C, whereas the onset for F_Ash_TX_PH is at -18°C. Secondly, B_Ash_TX_PH exhibited a higher nm(-20 °C) of 10^5 g^-1 than that of F_Ash_TX_PH ( 5 x 10^3 g^-1). On the other hand, previous studies on different combustion ash samples have reported that the opposite trend (i.e., ice nucleation efficiency of fly ash is greater than that of bottom ash; Grawe et al., 2016, ACP; Umo et al., 2015, ACP). We will discuss possible reasons for the observed differences. In addition, the results of complementary physico-chemical analyses via X-ray diffraction technique, Raman microscopy and scanning electron microscopy on both ash types will also be presented to relate the crystallographic and chemical properties to their ice nucleation abilities.