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Optical clock networks play important roles in various fields, such asprecise navigation, redefinition of "second" unit, and gravitational tests. Toestablish a global-scale optical clock network, it is essential to disseminatetime and frequency with a stability of $10^{-19}$ over a long-distancefree-space link. However, such attempts were limited to dozens of kilometers inmirror-folded configuration. Here, we take a crucial step toward futuresatellite-based time-frequency disseminations. By developing the keytechnologies, including high-power frequency combs, high-stability andhigh-efficiency optical transceiver systems, and efficient linear opticalsampling, we demonstrate free-space time-frequency dissemination over twoindependent links with femtosecond time deviation, $3\times10^{-19}$ at 10,000s residual instability and $1.6\times10^{-20}\pm 4.3\times10^{-19}$ offset.This level of the stability retains for an increased channel loss up to 89 dB.Our work can not only be directly used in ground-based application, but alsofirmly laid the groundwork for future satellite time-frequency dissemination.

113 km Free-Space Time-Frequency Dissemination at the 19th Decimal Instability